@pastanaga - There are plenty of jujitsu classes that are aiming to cater for casual students who just want to learn how to defend themselves. In fact, most short term self defense classes seem to draw on jujitsu moves since they are effective against opponents of any size.
I do think that there should be a distinction made between people who seriously want to learn it as a sport and people who are just there for a few lessons. It's not fair for the people who are serious about it to have to put up with those who aren't. Your fellow students can make a big difference to the experience.