How is Obamacare the "largest tax increase in US history"?

This seems unlikely, I would think that the largest tax increases would be related to WWII - just because it was such a huge endeavor. Politifact seems to confirm that suspicion:

Using that method, I guess so.

What method did you mean? Comparing aggregate Reagan-era increases against those of the other administrations?

Tempalski’s.

I just read that Forbe’s article and while I understand the logic of what they are saying, I think that saying it is a large tax increase is of course a lie in the sense that it will not be an increase of anything for most people. And it isn’t like folks who purchase insurance aren’t getting anything, they are getting insurance.