I wan't to express, that I disliked Rick and Morty season 3

[Homeless Nutter]

I have a different opinion. Sci-fi does have to do with technology and theoretical concepts to explain what happens to be impossible or unknown if possible in our real world. Fantasy either doesn't give any explanation or gives magic as an explanation. Rick - a scientist - turned himself into a pickle using science, not magic, thus making it sci-fi. A ridiculous sci-fi but sci-fi nonetheless.

Sure. I wasn't implying that the episode belongs in the fantasy genre, just that sci-fi has to take real life natural laws into account. The mad scientist trope does make it - technically - sci-fi. But the idea of people transforming into inanimate objects (and back), while retaining some human traits, like their personality, intellect, voice, face - that's something straight out of fairy-tales. But mostly - it's a wacky cartoon thing.

I talked about it in the OP. I do see it as a possibility that there are universes in which children are as mature as adults or at least for  some Mortys to be as mature as adults. What bugs is that the show never established that this is the case with evil Morty. Maybe the show doesn't want to tell it directly, but I personally don't see any (good) hints.
He does act mature, however his opponents act so immature that he comes across as adult like mature only in comparison to them. This doesn't prove he thinks like a kid, it just doesn't give any hint that he doesn't. These supposedly genius Ricks are so easy to manipulate that not only does it not prove that evil Morty has the mind of an adult, but he also comes across as a not so good of a villain, not because of his own traits, but because he has such weak opponents.

Perhaps. But have you ever wondered why the protagonist Rick - the Rick-est Rick of all - hates the idea of a Citadel, has very low opinion of other Ricks and is able to outsmart them with relative ease? Maybe the message is, that bureaucracy and conformity make Ricks dumb and ineffective - enough for someone like Evil Morty to exploit that.

Also - Americans elected Donald Trump to be their president 2 years ago. I rest my case.

I don't see any problem if they repeated the scenario. Evil Morty wasn't caught the first time, if he pretended that he is a normal Morty nobody would suspect him.

Yes, but the viewers - at least some of them - would probably notice. It's the creators' choice - whatever they do, they'll piss of some people. And clearly they wanted to make a political statement, of sorts, or at least they wanted to depict a crazy election - for god-knows-what unimaginable reason.

This time he could make a self destruct system on Rick so that nobody could find out he was mind controlled. The other Ricks know that evil Rick was mind controlled, what if they became scared of mind control? What if evil Morty took their fright to his advantage? They could've also make evil Morty try to mind control someone, but fail. They could've also had him pretending that he's a normal Morty while planning other things than mind control. 
Also, why would the creators worry about repetition, when they themselves repeated two times a joke in Ricklantis Mixup which they already used in Raising Gazorpazorp? Not only that, but they repeated the joke once in the  first appereance.

That's jokes. Having similar jokes is one thing, repeating the same plot is another. Sure - they could have done it. But the point is - they didn't have to if they didn't want to.

Call it "meh" humor if you will and you have the right to do what you want, but I don't think that it truly brings us together. So we all have something in common excluding our many differences and we are all equally bored. Look, I may have criticized it, but truth is, I find it harmless.

It's not "meh humor", it's "groan humor" - and I didn't make it up. Here in UK people tell each other old bad jokes as part of Christmas celebrations, so that everyone can sarcastically say "ha ha" and roll their eyes. Mr Poopybutthole - and many other jokes on "Rick and Morty" - is the same exact idea, imho - we all get to say: "That's a stupid name, a pointless character and the voice actor doesn't seem to know his lines. But it doesn't matter."

Sure - few people might not get it, especially young people, who are generally allowed to take entertainment too seriously. One kind of "groan joke" is a "dad joke", which is the kind of stupid childish joke, that parents tell their teenage offspring and laugh as kids roll their eyes and complain about being embarrassed by their uncool family.

And no - we're clearly not equally bored. Many people don't seem to have the same reaction to the last season, as you. The show is obviously gaining popularity, which is why it's been renewed for unprecedented 70 episodes. And again - I'm not a die-hard fan of the series, but I enjoy it for what it is. And if I stop finding it enjoyable - I'll just stop watching, no big deal. I'm pirating it anyway...