Because that detail, like the $100milliom limit are irrelevant details subject to change. (Most) People have the ability to synthesize issue and are worried of the proposal's fundamental core:

"Do we want the government to tax unrealized gains?"

No. I find it very scary frankly, even though I believe that the top 0.01% of the US population are parasitical and their financial and political clout should be reined in.