Do you think this sale was intended as a union-busting move? It sounds like they're not retaining staff with the sale, and this timing seems to match with Bandcamp's staff unionization efforts.
In my middle management experience, being profitable and owned by a company that didn't share the business domain was best as they mostly left us alone as long as we were profitable. When they finally got bought by a similar business, that's when they tried (and failed) to merge jobs. I've since left but they've recently been spun out yet again.
bandcamp staff unionizing might have been a consideration in deciding to sell the company, but i don't think it's fair to call that "union busting".
It's impossible to know what Epic is thinking know, or even when they bought BC, but 6 months sounds like how long it would take to sell Bandcamp off as a retaliation for unionizing.