I didn't read this particular bill but encountered them in the past when I was a service manager. Dealers have to pay Ford for access to online training and all but current model year info, in 2017 when I retired the "value package" cost us just North of $5000 per year. It wasn't mandatory that we buy it but no online training means certifications expire and warranty claims no longer get paid, so it was mandatory if you wanted to stay in business.
Without spending the money, time, and effort to do the Ford training- which they do not have access to- giving independents access to more diag info would create more problems than it could ever fix. I never kept track of training expenses but it had to run $8000+ per year for my 8-11 tech crew.
ASE certification is barely better than worthless, their cert tests are multiple choice and teach exactly nothing, an untrained chimp would statistically get 25% right. From my decades of experience, most independent shops don't know what they don't know. The good ones know when to send their customer to a dealer or sub out the job themselves.
If this bill passes and someone gets electrocuted trying to fix an EV they really aren't qualified to work on, their survivors will probably sue the manufacturer for making "dangerous" information available. Don't laugh, in Connecticut people can sue gun manufacturers if their product performs as designed and someone uses it to illegally kill another person.