There are lots of questions about uninterruptible power supplies that are
improperly tagged as apc
There are 95 questions tagged apc
Manually retag the 13 remaining questions.
Synonym or delete apc ? Blackhole APC
I think you'll find that when a system administrator mentions APC it's automatically assumed we're taking about a UPS, not a rather minor bit of software. Your statement that "questions about uninterruptible power supplies that are improperly tagged as apc" makes no sense. To put it simply, you've got it back to front and questions about "Alternative PHP Cache" are incorrectly tagged and may well be off topic to boot.
APC makes more than just UPS devices. I would submit using apc-ups is overly narrow.