Blocking for not supporting JS isn't illegal nor a violation of the US ADA. You can add requirements for disabled people to access your services as long as it's

Blocking for not supporting JS isn't illegal nor a violation of the US ADA. You can add requirements for disabled people to access your services as long as it's reasonable, and the prevalence of screen readers that work with JS turned on likely qualifies requiring JS a reasonable request. It'd be like saying "you can't deny someone using a IE8 screen reader by only offering TLS 1.3".