That's absurd that they shouldn't pay ANY attention. You can go too far in both directions. The stock price is an indirect indicator of the material impact of the regulation.

Regulators should pay absolutely zero attention to stock market. If the stock price crashes, it's because the company's value was derived from the exploitation and abuse that regulations are supposed to prevent. They were never supposed to be that valuable in the first place.

Regulations should cause as much damage to stock price as possible. We should measure the effectiveness of regulations by how much they tank the stock of affected companies. Real change often affects the profits of corporations. If nothing happens, then I doubt the new rules are actually gonna change anything for the better.

I think you're saying the purpose of regulations should be to hurt the stock price of companies. That's seriously crazy. Why not write a regulation simply outlawing public stock markets?

The purpose of regulations are to make people's lives better. That could mean protecting them from harms, or preventing other undesirable outcomes. There should be a cost benefit analysis applied there. Of course some things are hard to measure so there will be arguing on the margins.

The place I do agree with you is that if a company's business is doing regulation compliance (see: Intuit), then their viability shouldn't be a factor at all.

I'm saying regulation is likely to be ineffective if it doesn't hurt stock prices.