It's the natural consequence of a plurality voting system.
Conservatives remember H. Ross Perot spoiling the election for George H.W. Bush, and throwing the election to Bill Clinton. Progressives remember Ralph Nader making the contest between Al Gore and George W. Bush close enough that G.W. was given the election by a Supreme Court stocked with his dad's buddies.
Voting for third parties is a terrible political strategy in the United States. The spoiler effect is real. I'd go so far as to say that our plurality system all but guarantees bad candidates--it's not the fittest that survive the primary election process, it's the most memorable, the one who we feel will best appeal to our neighbors.
Going further, I'd suggest that having a strong majority political belief is a major liability in U.S. elections.
When Bill Clinton was elected, the nation was largely happy with the center-right GOP of the time. As a result, the further right bloc had the confidence and diversity of small differences of opinion to split and lose the whole thing. (Never minding the fact that Bill Clinton was far to the right of traditional Democrats).
The same was true with Nader and Gore in 2000. Bill Clinton's policies had been so popular that people largely wanted another Clinton, but perhaps a little more progressive. Disagreement ensued as to how much more progressive, and thus we had Nader and Gore losing to the much more hawkish right-wing George W. Bush.
So, in the U.S., you're best off being part of a popular political leaning, but pray your political leanings don't grow so popular as to result in a split.
My personal feeling is that this country desperately needs to move past plurality voting. The easiest path to this is for states to apportion their electors based on ranked choice voting. It doesn't solve all our problems, but it does remove the spoiler effect. With luck, that would allow us to have less shrill, more substantive candidates--even if the major parties continue to dominate.