Obvious photoshops are different. This example is funny because it's obviously not real. The truck one is intentionally pretending to be real and not entertaining at all. That's the difference.
You could post pictures in a community called "photoshopped memes" and every post would have people in it telling everyone it's fake. Some people are special like that.
Bruuuuuuuuh. You realise that most people moved here from reddit 1+ year ago? I've been following this community for years before I quit reddit and this commnity always had it's own specific set of rules. I know it may shock you but ~99% of all lemmy communities are in fact based on reddit communities. I know we hate reddit but let's think for ourselves please...