it does apply to websites but it depends on some things. For example if you build a SASS application and provide it to a company. A big vector for this type of legal issue for a while was POS systems there was a big lawsuit a while back where all the major retailers were sued so that’s mostly been addressed. If its required as part of a job being performed by someone with a disability aka not WCAG 2.0 compliant you could get in sued. If you do any kind of work that is tangentially connected to US federal funds or serve a government RFP(federal and most states) you will have to be ADA compliant.