It's wrong to do so if you're a teenage hacker who just discovered scripting, and it's wrong to do so if you're a government.
And the latter is IMO much worse than some teenage kid playing around because of scale, impact, accountability and the fact that, in a "democracy", the government should be influenced by the people and not the other way around.
Do you agree?
[ ] Yes [ ] No
I try to never conflate the meaning of the words "illegal" and "wrong", as they are rather orthogonal, even if many people do not realize this.
And I think it's wrong (unethical) to do so for a multitude of reasons. Two main ones are because it's misleading to people reading/interpreting the results, and that it's actively trying to sabotage the intent of whoever set up the poll.
Don't get me wrong though, if we're talking about a stupid or silly poll, on a stupid or silly site, or if it's in the context of a really good prank, etc, it can be a forgiveable type of "wrong". In fact in certain circumstances one could even argue that it's not actually completely wrong, simply because I wouldn't want to live with a system of ethics where pranks are never right. That's a tricky one (as is often the case with discussions about ethics).
However, that's not really the type of manipulating of polls we were discussing here.
I'm more alarmed by the email spoofing. Isn't this the same as manufacturing evidence? Consider: An entity is under surveillance, however the powers that be decide the scope is too limited. What better way to invite scrutiny than ensuring an email from the desired target arrives in the monitored entity's inbox?
Yes, their "results" are often read on daily news broadcasts.