Not quite every company. The ADA prevents an employer from asking about disabilities during the interview process. They CAN ask after an offer is made. Employers are required to make reasonable accommodations for persons with disabilities.
The reasonable accommodation is the catch and where the disputes fall. Epileptics can do most types of white collar jobs but there are some things which fall outside the protections of the ADA. An epileptic can't be an airline pilot or bus driver, for example. Probably can't work in construction either. Essentially the more physical the work is, the greater the risk for injury, the more likely it will fall outside of the ADA's protections.
We still have plenty of options. The ADA just isn't a complete pass.
Some info from the federal government: