In the other thread, we were talking about this exact thing: Bigotry and Xenophobia in the west being used by terrorist recruiters to get more people to sign up. We were citing it as a major reason why giving in to those things, even in the smallest of ways, is a stupid idea. And yet, here you are again, with the same idiocy.
This is definitely not so cut and dried as you paint it, its a tradeoff. If islamophobia in the west causes some additional % of muslims to radicalize, but also causes the immigration policy to tighten so that the pool of muslims to recuit from will be smaller compared to situation with free immigration, then the net result can very well be less extremism than in situation with free immigration and no islamophobia. A slightly higher percentage from a smaller pool can result in less overall extremism than slightly lower percentage from a bigger pool (depending on the exact numbers).
And even if we agreed that less islamophobia would lead to less radicalism, that ship has sailed and most likely wont be coming back. You simply cannot expect people to have regular islamist attacks in their countries without getting more islamophobic - that might work with robots, but not real people with real emotions. If the current situation of regular islamist terrorist attacks is the new normal, islamophobia in Europe will only increase, not decrease. Unrealistic solution, (decreasing islamophobia to achieve a little lower radicalization rate), is not better than no solution at all. And I think the effectiveness of such solution would be limited anyway - islamophobia is definitely not the only or even biggest driver of radicalization.
Another thing to realize is that this process can only work if there already is a sizable muslim minority in your country to radicalize. If you dont have muslims in your country, then you cannot be threatened in this way, no matter how islamophobic the country gets, since you have no one to radicalize in the first place. The west has already a lot of muslims, but we dont. And this is why we (V4) must ensure that our countries stay like that. If we dont ensure that, we end up with the same troubles as we witness in the west today. Perhaps even greater troubles, if the theory that more islamophobia leads to more radicalization is correct - since V4 countries are more islamophobic.
This is of course specific to countries that almost dont have a muslim minority - if you are not from such country, feel free to disregard this last paragraph.