I think you're overstating the situation there. My understanding is that FPTP tends to result in a 2 party system, but I have not heard it asserted that it guarantees such. And there are counter-examples listed on the Wikipedia page for Duverger's Law[1], so we know it doesn't always happen.

It's also important to keep in mind what "two party system" really means. In the US, for example, it is not the case that every elected official belongs to one of two parties. There are both independent ("unaffiliated") office-holders (in what would be considered partisan positions) and 3rd party office-holders. The Libertarian Party, for example, usually claims approximately 600 elected officers nationwide (not all in partisan positions however) in average years.

So, net-net, while FPTP is a bad system in many ways, one should not feel that there is no value in voting for 3rd party or unaffiliated candidates in such a system. Under some circumstances they do win, and in other cases they at least affect the outcome, which - in turn - affect the public discourse - and they may impact the Overton window as well.

[1]: https://en.wikipedia.org/wiki/Duverger%27s_law

Mindcrime has already said much of what I would have, but ignoring FPTP has advantages as well, mainly, that it allows people actually vote their conscience, for better or worse.

I can't argue that it isn't 'throwing away' your vote, in the short term, but over the very long term, there needs to be some people throwing away their vote in order to encourage more to do so such that eventually the landscape changes.