Ah, so this bill will tax gains from productive activities like investing in and building companies, while exempting gains from rent seeking activities like real estate. Why am I not surprised?
Stocks are held by rich people and techbros, in the minds of the public. Whether something is valuable or not valuable depends on who you empathize with. Right now occupations held by the wealthy are disliked and unpopular.
Really you should just tax income at high rates and investment at near-0%. When people cash out their investments, tax them at ordinary income rates. This is how your 401(k) or IRA already works. You'll need to raise taxes on the affluent who spend instead of save, but that's not a bad thing.