Sure that possiblity exists. But that scenario is a strict subset of the scenarios in which unionization would force people to support views to which they are opposed. If there is exactly one employer in your area you're hosed union or not.
Furthermore, there isn't anything that's preventing those employees from voicing their opinions without a union. The story linked in the OP is exactly that. Unless tech companies are firing thier employers for their political views, employees can make their views known regardless of union status. While we have seen a few instances of that, most were views that I doubt the average pro software developer union person wants to see defended (then again a lot of people proposing unionizing developers want to limit H1Bs so you never know).
Contrast this with people who are against what the union is doing. The only way to avoid this is to leave the union. In some states (including California) this may mean leaving the entire field of work. Right to work states guarantee the ability to work without union membership, but many (most?) tech jobs are not in those States.
Being able to quit a job over a moral objection is a painted as a luxury to most employees (whether it actually is a luxury or not... I think is less relevant than all the media we're fed reinforcing the fact that having a job is a privilege we're lucky to be allowed)
Thus to depict union membership as protecting workers' ability to avoid taking part in the endorsement of views is nonsensical. It is strictly harder to quit a union than to quit one's job. Because the latter not only involves quitting one's job, but also finding new employment in a different field.
(Did you mean "former"?)
I think you're being more than a little hyperbolic. Unions can't force employers to not hire you if you're not a member (in fact most employers probably would prefer non-union employees because the employees have less negotiating strength).
Not to mention that historically unions have been the catalyst for workers rights legislation (like the 5-day work week, and 9-5 hours, overtime pay, and so on). So even if you aren't a member there are obvious benefits to employees who aren't members of a union (in the long run).
This is not the case. At least, it is allowed in States that have not passed legislation to that effect. Many (usually liberal) States have not done so, as it would weaken the power of unions.
And do you know why it is so? The popular adage is "gun lobby throws money at representatives", but it's actually not true.
The reason why gun control doesn't get traction despite popular support is because those polls that measure support or opposition don't measure the dedication of people expressing it. The majority, when asked about gun control, support it, yes - but most don't feel particularly strong about it, and extremely few consider it a make-or-break single issue. So when it comes to voting, politicians know that they can get those people's votes even if they don't go for gun control, riding on other issues.
OTOH, NRA (and other gun rights orgs) have a very effective resource, and that isn't money - it's membership. Specifically, it's the subset of its members that is laser focused on gun legislation, and the majority of whom consider it their single most important issue. Because of that, they're likely to turn out in the primaries, and vote based solely on that one thing, ignoring everything else. Furthermore, NRA (or rather NRA-PVF specifically) facilitates it by compiling dossiers on various candidates in all races across the country, and publishing them together with voting guides. So what this all means is that any Republican who openly supports gun control will find it hard to get through the primary. And, conversely, not supporting it is not a big downside in the general (D voters will vote against you anyway, and R voters will vote for you anyway).
This is changing lately with the rise of left-wing, ideologically motivated groups that target primaries in a similar way, like Indivisibles, which means that Dems these days are a bit more likely to pick it up. But it's still a litmus test for Republicans, and for as long as that remains the case, you're not going to see 70% popular support translate to 70% legislature votes.
By the way, we had a very good demonstration of this recently. Remember the whole bump stock kerfuffle? When ATF announced that it's reviewing its categorization of them, there was a public comment period. Here's how it went:
"Of the more than 17,000 public comments received so far by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), a review by Reuters of 4,200 turned up only 10 favoring the bump stock ban. Almost all the rest criticized the proposal as heavy-handed, unnecessary or unconstitutional."
Funnier still, most comments expressing support for the ban were form letters, while most comments expressing opposition were not. This despite the fact that over 80% of the population support the ban, according to the polls - just not enough to bother leaving a public comment on the Internet expressing that opinion, much less prioritize it in their voting choices.
Same deal with unions in tech. Say you're in favor of immigration for high skilled workers. Most unions are against immigration when it has the potential to increase the supply of labor in their field (because increased supply = lower costs of labor).
There are certainly unions with bad politics. The ideal is a union that is embedded as part of a broader pro-worker movement that supports migrants, women, other minorities, the unemployed, etc.
In Australia, high schools are ranked based on final exam scores and that's something teachers already hate. But to tie it to pay would lead to an even larger conflict of interest and attempts to cheat the performance indicators. When I was graduating high school, I noticed that all of our raw marks were reduced right before our final exams (they were reduced because the metric takes into account whether the school was "harder" on students than the national exam or "easier" on them, and rewarded "harder" schools).
If this was just done to change a ranking, imagine what would happen if teacher's pay was linked to performance. Hell, what about rural or "bad neighbourhood" areas? Should we always and forever doom them to have bad teachers because all the good ones go somewhere with better pay? This is already happening (because working for a higher-ranked school is better for your career) and is pretty bad -- having performance-based pay would be a disaster.
I think that's a good point -- unions are not perfect and may support the interests of their members over the interests of other workers or society at large. However, in my view they are far preferable to any corporate board of directors, which represents only the interests of the owners of the company. Politics is struggle, it isn't just opting out of things you don't like, or else you'll end up a hermit. it's organizing for representation and power, and unions are one example of that kind of organization. An imperfect one, yes, but far preferable in my view to none at all