Doesn’t that constitute impersonation, or is it allowed since it’s supposedly obvious to be parody?

I guess it's mainly un-sueable because the reference is very implicit (nothing but the last name) and using the name Swift by itself constitutes neither impersonation of someone specific nor a Trademark violation or anything like that.

And Taylor Swift actually is invested in data security, so it's a compliment :) That's no reason against filing a lawsuit but much less for filing one.