2018!Thanos and Jigsaw are perfect examples of hypocritical extremists in my opinion.

This does admittedly depend on what the villain is hypocritical about like if their goal is to purge the world of an action they're doing themselves in pursuit of that goal that's hypocrisy that doesn't really prevent them from being an extremist

Another perfect example is The Legend of Korra baddies, with the exceptions of Unalaq, are mostly extremist, anti-villains even. Al of them have shown one way or another are pretty much hypocrite but their hypocrisy is pretty negligible as they have been shown to really want good despite some ounces of hypocrisy, with Kuvira outright redeeming as a result of this.

In comparison, Unalaq is a perfect case when the hypocrisy does make a villain not an extremist. His own actions go far against that characters n-universe call him out as a power-hungry villain, and really, I think the best indicator someone really is not an extremist is through their end goal as well and how much it contradicts their good intentions to a pretty big degree, which is the case with him, is bringing forth the end of the world despite his intentions being spiritual harmony. (The fact that he was written to be an extremist is a hilarious icing on the cake).

All in all, it usually depends, but if the level of hypocrisy is pretty minor in comparison to how they actually go to achieve their well-intentioned goals, especially if their endgame do not go against their motives

There are other extremist who fall under there but not always like others say.