Indeed, just saw it (was replying in flow).
Essentially you appear to be pointing out the different degrees of belief within faiths, religions, and societies. Some are extreme takes. I think we all sadly accept that. You are suggesting that it is perhaps 'easy' to filter the more 'extreme' thoughts defined as such by our societal definition. In theory, if I could quietly refuse entry to members of (say) a violent extremist group annexed from a religion, great. In practice? Virtually impossible, not the least of which because sadly, due to the atrocities and loss suffered globally on a daily basis, more extremists are created where there were previously none. Imagine your home being bombed, your family decimated, when all you want is to live your life! Survivors stand a huge chance of becoming radical. Sadly unsurprising; we can't even go three pages here without anger breaking out!!!
Polarization is the greatest of enemies. The more we run and hide, the more we cry differences, the less we understand what we have in common versus not, the more extremism wins (and with it fat cats getting fatter).
I am all for proper immigration controls. I am all for keeping bad people and influences out. Equally, I think it is VITAL we recognise the ENORMOUS amount of richness immigration and multi-culturalism brings. We all have much to learn. I agree with those who say when moving here it is important to integrate, but equally that should be a balance. We can never forget the lands we 'took' and the cultures we 'appropriated'. We should, IMO, never stop trying to come together where possible.
This is obviously an enormous subject, but for me, when agents of fear and hate look to actively polarise people off the back of disgraceful isolated acts of violence, we must resist, we must be brave and we must double down.
Fear is a mindkiller...