There's a reason why stand-up comedians film their specials in front of an audience and don't film themselves telling jokes in an empty room. The latter wouldn't be seen as funny even if the jokes were the same.
Comedians doing standup are including laughter based on their audience enjoying their comedy. Even shows that were filmed in front of a studio audience with prompts to laugh are likely to get some genuine laughs.
Sitcoms that use canned laughter are trying to force the audience to think they are funny, even when they aren't.
Also, a lot of the time it doesn’t mean there isn’t a real studio audience actually laughing at the performance. It’s just much easier to layer in canned laughter than record the actual live audience. This isn’t the case for stuff like SNL but a lot of live to tape stuff will use canned or prerecorded audience noise on top of a real audience.