Some US lawmakers want to ban lawmakers from stock trading

Government officials and employees sometimes put their investments in blind trusts to avoid conflict of interest. They give up control, or even knowledge, of how their investments are managed for the period they are in office. Seems like a good plan for the US Congress.

Finally, now we can put crooks (that's the majority) in the senate. Not being able to do anything remotely illegal, there's no need at all to distinguish scoundrels from good folk.

There are so many big issues in questions like this that it is had to meaningfully discuss unless people are coming from the same perspective.

Voters are entitled to representation of their choice (claim). Any restrictions on qualifications or behavior of a representative are effectively restrictions on voter choice. Assuming that unfettered choice is among the major aspirational goals of designing government, there must be a compelling reason to limit that choice.

In the US, there are already tools available to moderate the behavior of members of Congress - which tools are freely available to other members of Congress at any time. The US Constitution includes language (Article 1, Section 5, Clause 2) providing for both the House and the Senate to expel members based on the concurrence of 2/3 of the respective house. This mechanism essentially limits the Federal Government's ability to expel elected representatives absent the highest form of agreement required, a requirement that suggests that the behavior must be so grave that 2/3 of a house acting in good conscience would believe it appropriate to expel a member. What this means is that if a member does something objectionable (whether it was declared objectionable before or after the fact), that member can be removed - no additional laws, rules, etc. are required.

In the context of unfettered (or minimally restricted) choice of representatives combined with a mechanism for Congress to remove bad actors (assuming the act was so bad as to have 2/3 of members agree), grandstanding about yet another rule/law/etc. that can only result in Congress saying, "Bad!" should be seen as the political ploy that it is. If a representative's constituency re-elects them after the bad act (assuming that its occurrence was reasonably knowable), then the people have spoken. This is very similar to Trump not disclosing his tax returns - he didn't, he got elected, and because the Democrats wanted to see them, they tried to make law that would have compelled any candidate to disclose their tax returns. Rather than accept that people were willing to Support Trump in his intransigence, the Democrats tried to change the rules to win (future election) by other means.

Representatives are not employees. Treating them as such misses the point of their existence.

People in favor of pretend restrictions or criminalizing otherwise lawful behavior to get around the inability to expel a member should explain what compelling reason exists to supplant the will of a representative's constituency.