Can people quit acting like building health on Soraka is bad?
It's not bad. Yes, getting a Warmogs will increase the cost of her heal by 80 health, but she will still have 720 extra health left.
Let's say you had 2000 health before getting a Warmogs, and 2800 after getting. Without Warmogs it costs 200 health leaving you with 1800. With Warmogs, it costs 280 leaving you with 2520. Lets say you were at 20% health. That's 400 health for the non Warmogs Soraka and 560 with the Warmogs. The non-Warmogs Soraka heals and has 200 health and the Warmogs Soraka heals and has 280 health left.
In all cases, the Soraka with the extra health has more health (Duh). I would also like point out that the extra regen on a Warmogs would allow Soraka to recover the health cost in 10 seconds, 3.3 if she can avoid taking damage.
Now there is the potential issue of it being the only ability that costs % max health, but that doesn't make building health bad on Soraka.
Perhaps there are better things to build on her, such as AP or Mana, but again, the only thing Soraka loses is what she could have built.
Building health on Soraka isn't bad.