I'm glad you bring up this topic. I think that explanation makes a lot of sense: behavior that is wrong, but wrong in subtle ways, is good for you to notice -- you I.D. outsiders -- and so you benefit from having a good feeling when you notice it. Further, laughter is contagious, so it propagates to others, reinforcing that benefit.

I want to present my theory now for comparison: A joke is funny when it finds a situation that has (at least) two valid "decodings", or perhaps two valid "relevant aspects".

The reason it's advantageous in selection is that, it's good for you to identify as many heuristics as possible that fit a particular problem. That is, if you know what to do when you see AB, and you know what to do when you see BC, it would help if you remember both rules when you see ABC. (ABC "decodes" as "situation where you do AB-things" and as "situation where you do BC-things).

Therefore, people who enjoy the feeling of seeking out and identifying these heuristics are at an advantage.

To apply it to your examples:

1) It requires you to access your heuristics for "displayed on a TV screen" and "on top of a TV set".

2) It requires you to access your heuristics for "muffin as food" and "deficiencies of foods", not to mention the applicability of the concept of "baldness" to food.

3) Recognizing different heuristics for interpreting a date specification.

4) I don't know if this is a traditional joke: it became a traditional joke after the tradition of minister/priest/rabbi jokes. But anyway, its humor relies on recognizing that someone else can be using your own heuristics "minister/priest/rabbi = common form of joke", itself a heuristic.

Food for thought...