Mr.Beans is a very specific type of comedy, it uses a lot of techniques from the silent-era movies where dialogue couldn’t be given through speech so it had to be done through the actors… well… acting. It had to be very physically expressive in order to convey the same emotions one or two words could give and that is more difficult than it sounds.
However, the show was also a product of its era. The main character is literally a child in a man’s body and the comedy sometimes is through the paradox of someone so innocent and naive in our day-to-day lives.
The innocence and simple comedy also relates to a time after the World Wars, it was what the people wanted and needed.
Mr.Beans is not intended for the viewer to relate to. He is not a “realistic” character, he has no background, it is never explained how the hell he can live, or has an apartment or doesn’t die of starvation from his mere stupidity. Because those things aren’t important for the show. For its intentions and purposes, the show doesn’t need to be complex and deep. Nor the people wanted those things back in the day, their lives were difficult as it was and watching something light and simple was their escapism.
Another comedy show that made a lot of success and deals with this simple and very innocent and naive type of comedy is Chaves, a show that made a lot of success in Latin-America.
Nowadays the comedy of these shows might not work very well because we (newer generations) passed the trauma of the wars and we are in a sort of more cynical or realistic comedy mood. This isn’t a bad thing on itself, comedy constantly changes and reflects the mood of its time. Another example: how in the 80’s and 90’s (maybe even older) we had an avalanche of family sitcoms were the father was portrayed as an idiot slob and people loved it. Nowadays you will find people getting upset by this trope and wishing for different (and hopefully more positive) portrayals of the father-figure.
So yeah, Mr.Beans is a product of its time with a very specific type of comedy. It has its strengths and its lows and it is understandable that someone might not like it.