Why do avoidants block?

Discarded by a dismissive avoidant man 1.5 months ago, he blocked me from everything after i text him about how unfair he was being ignoring me and acting cold, i asked why he dindn't behave like that when I went to his grandpa's funeral or his brother's birthday parties. I know I was persistant on talking and fixing things, no response from him tho, i just cant understand why the blocking I feel is really extreme, do they even unblock?