To that point, shouldn't it be what the listeners (collectively, not person by person) say it is? Same goes for the discussions around how adult contemporary isn't adult contemporary etc. If "It's my Life" works for the audience, where's the problem?
There isn't one. And interestingly, more than a year ago in one of those "AC isn't AC anymore" threads, I pointed out that the Ramones' "I Wanna Be Sedated" was testing well with women in their 30s and 40s who consider it a party song. And now, here it is on KRTH.