There is no problem with an individuals choosing not to engage based on their own experience. The problem with cancel culture is that we are encouraged to treat people as "cancelled" based on hearsay.
You're under no obligation to do anything. Individuals are simply exercising their own right not to engage based on their own experience.
From other comments, you seem to be drawing a distinction between "social pressure" and "individual choices". Can you explain when one becomes the other?
I don't think there's a clear bright line, any more than there's a clear bright line between being avoiding individuals you dislike and discrimination. That doesn't mean the distinction doesn't exist.
If one shopkeeper won't serve you, they're exercising their own rights and you can take your business elsewhere. But if every shopkeeper won't serve you, you're probably being discriminated against. I don't presume to draw the line precisely, but we recognise the difference.
From other comments, you seem to be drawing a distinction between "social pressure" and "individual choices". Can you explain when one becomes the other?