That's a cop out.
Fans will boo the heels if the heels do their job and act the way they should. Look at ECW for instance and guys like Shane Douglas and Raven. Great workers but also huge heel workers because they knew all the subtleties to draw heat.
And before you say "well that was in the 90s"
There's CM Punk who despite being an Indy darling drew great heat when he was apart of SES and was still doing a stellar job with Heyman in 2013.
Fans will boo if the heels do their job instead of hitting the panic switch and hitting non-sensical high spots because the fans aren't responding to the match as well as they'd like.
Meanwhile guys like Rusev and Sheamus know their job and make a lot of good choices inside the ring that earns them heat.
In fairness, I think the babyfaces are doing an even worse job than the heels at present but that's a subject for another topic.
On CM Punk - he drew major heel heat in the SES because his promos literally bored people to boos. I spoke to several friends of mine who all thought he was dull.
I like Sheamus, but come on - he's not particularly special at what he does. He just looks silly, bullies smaller opponents and - and this is a big point - he's not American.
If Sheamus O'Shaughnessy was named Bill Smith, he wouldn't be the worker he is today imo.
People like me don't care if you're a heel or a face - I'll cheer anyone who entertains me.
Imo the only bloke who is a brilliant, brilliant, peerless heel is Heyman.
Let me ask - who is these days capable of drawing X-Pac heat?