10% surtax on short term capital gain to fund Social Security makes no sense whatsoever. If anything it amounts to highway robbery. The time period that a trader has income from stock trades does not even count in the Social Security benefit "quarter" counts. Why should stock traders be forced into paying into a system that they are not even covered under? If you propose stock traders should be subject to the same self-employment tax and social security/medicare tax/benefits as someone who buys and sells groceries, I may agree with you on principle though it would still cut into my wallet, actually potentially more than 10% depending on income level.
As for more funding for SEC, the SEC is piling up a sizable nest egg just on the SEC fees from all the stock sales. SEC can be more than adequately self-funded.