What was the thought process behind Taric's ult?

What were you guys at Riot thinking when you created an ability that gives complete invulnerability to an entire team for a few seconds? In what world is that a good idea? His ult is absolutely disgusting, and it feels awful to play against it.

They can still be affected by cc? Oh yeah no worries we can just waste all of our hard cc countering one ability without even being able to damage them while they're locked down. It has a delay? No problem, you just have to kill their entire team in the short window before it activates. Oh you're trying to defend your inhibitor turret and he's using it offensively? I guess that's just too bad, maybe next time you'll think twice about trying to defend your tower from Taric.