> they would consider weed sales illegal?

Weed is illegal under US law. Nothing meaningful about the federal prohibition on weed has changed for decades.

AFAICT all dispensaries are admitting federal crimes when they file federal tax returns. I believe the statute of limitations on controlled substances violations is 5 years, meaning dispensers are theoretically always under threat that the next administration will bring down the hammer and prosecute them for sales occurring today.

The IRS doesn't care if your income is legal or not, they just care if it is reported truthfully and the taxes owed on is are paid.