If you nevertheless are certain that that was or is the goal of one of the US's two major political parties, then you've reached a perplexing conclusion based on, I can only guess, no evidence, evidence imagined, evidence misunderstood, or evidence contained in a source that should be tossed into the garbage can.
This critique had its heyday in the 2000 election. I can't fathom still holding fast to it. The last 26 years have been a continuing, relentless stream of evidence to the contrary.
Let's say in the main election 45% of the population will vote for whatever candidate represents side X, 45% of the population will vote for whatever candidate represents side Y, and 10% is more-or-less in the middle.
If, during the primaries, side X votes for a far-X candidate, they will definitely lose the middle 10% to a moderate-Y candidate, leading to a strong Y victory. But if side X votes for a moderate-X candidate during the primaries, the main election will be moderate-X vs moderate-Y, and they have a pretty good chance of securing the slightly-more-than-half of the middle they need for an X victory.
Of course you now end up with a lukewarm moderate X victor who isn't going to represent your far-X views, but at least you're not dealing with an even worse Y-side victor.
The real solution is to get rid of the winner-takes-all system inherently resulting in a two-party election, but Good Luck doing that kind of overhaul!
For example, ranked-choice voting would reduce the spoiler effect and allow you vote for your real choice, however it would not (on its own) change that races have a single winner, who eventually "takes all."
This matters because even if it's preferable to have both, ranked-choice is easier to introduce incrementally and with fewer amendments to various constitutions.
The UK has winner takes all parliamentary elections but still has multiple parties represented in it. There seem to be a lot of other barriers to other parties in the US doing the same.
Your sentiment starts out fierce: "constantly, actively..." and is immediately cut short "... choose to (only?) vote it that way."
You point out that voicing one's interpretations of the 2nd amendment is powerless - but voting, reduced to such a miniscule gesture, is also. The choice between a galloping right wing and a stagnant center-right is no choice at all. American elections are a facade for decisions already made on top. You can't vote it out.