You need to take a deep breath and reframe this
Their initial questions and skepticism were nothing personal against you
Their family member had been scammed and hurt previously, so they were right to feel nervous and want to protect him
They did not know you, and were not suspicious of you personally, just the situation
You need to acknowledge they did this out of love for him, and that since then, they have tried to get to know you and you have blanked them
What were the questions you found unacceptable and we can tell you if they are just common questions in UK families?
Can you give any examples of the racist comments?
Honestly, if you want to stay married, you need to give his family a chance
You have friends, so have the ability to be sociable. Please stop thinking everything needs to be so rigid and 'black & white'
If you really love your husband then try to be a little bit flexible for his sake. It's going to be a miserable life and marriage when you cannot share any time with extended family together
If after this they do anything specifically nasty or racist in the future, then absolutely call them out and don't see them, but don't rule out all family relationships forever