I agree with the premise that conflicts of interest are a real problem. No one wants a senator trading on non-public info from a committee hearing. But banning individual stock ownership outright is a blunt instrument that misses the target. It treats the symptom while ignoring the actual disease: insider information and enforcement.
We already have laws against insider trading. The issue isn't that officials own stocks; it's that they trade on privileged knowledge. A ban on ownership doesn't fix that. It just drives activity into blind trusts or family members, which creates new loopholes and less transparency. Meanwhile, you're imposing a massive financial penalty on public service, which already discourages qualified people from running.
The better approach is stricter disclosure, mandatory cooling-off periods, and aggressive enforcement of existing rules. That solves the conflict without destroying the right to participate in the market like a normal citizen. Don't ban the tool because some people misuse it. Fix the oversight.