Do Haredim join the minyan?

I heard from my father that because the Haredim have separated themselves from us, they often will not eat our food, will not enlist with us, have separated themselves from us in every cultural and social aspect, etc. They do not join a minyan, such as a Cohen who eats with a donation that Israel does not join with him for the zimon, and therefore someone who is careful about fancy kashrus and cannot eat with me cannot be called with me, and likewise, and for other reasons in addition, he cannot join a minyan because he has separated himself from us.
What do you think?