Unless you're assuming that the Titans lied to their mechanical servitors, the 'couldn't destroy the Old Gods because conflict empowers them' doesn't fly.

First off, the Titans gave a reason: they couldn't destroy the Old Gods without destroying everything else on the planet, too, which they were loathe to do for whatever reason.

Secondly, why would they lie? After all, if conflict literally empowered the Old Gods, wouldn't you want the jailers to know that? Heck, given the Old Gods' tendency towards shadowy manipulations, it makes far more sense to imply that they gain power directly from conflict as a way to convince the servitors to avoid it, or at least take extra care of the cells when conflict erupts.

And while we're on the subject, a window depicting the sha in Ulduar (if that's what it actually is) doesn't prove anything beyond the Titans thinking the sha were relatively significant for some reason. Or maybe just that it was a pretty picture. That there is some connection is inevitable; the Old Gods have touched every species on Azeroth to some degree or another.