My second pet peeve is the various different (and unrelated) meaning of the word 'ihr', which can mean in turn you (plural pronoun), her (pronoun), her (possessive determiner, as in "her book") and their (determiner). Why in the world would you reuse the same word for so many different meanings?
My favorite thing about German is that things are pronounced as they are spelled and vice-versa.
"Incredibly stupid" sounds a little derogatory. They are not particularly necessary for understanding the language, the correct gender/article for certain nouns are even subject to heated debate between regional dialects, and I agree, if you are coming from a language without these rules it might be hard to grasp/integrate. Nevertheless, I would not go as far as to say they are incredibly stupid.
Consider, English also has he/she, him/her, his/hers. You just got rid off the "the"s, AFAIK (or German is the only Germanic language that adopted it from Latin, but I am no linguist).
But gender is the easier part, the cases make it difficult: Similar to the English "he/him", we have declination of articles: "einen/einem/eines". This seems terrible for English natives. Together with constructs of "den einen/dem einen/von einem/vom einen/zu einem/auf einen/auf einem", so you need to memorize ways of saying things and at the same time apply the case accordingly. It can make a huge difference in what you are trying to convey.
"Von einem ..." is "... of one" (indefinite article), where
"Vom einen ..." (Von dem einen) is "... of the one" (dem is the article, einen is actually a counting pronoun, not sure this is the right name).
Yeah, sorry about that, I just get a bit frustrated when I encounter languages with them, because they, for me, feel so unnecessary.
I don't feel that comparison is fair, and I consider the English a lot more intuitive, since it's an indication of the gender of a person, which has a gender, and not of an object, which doesn't. They are more similar to "er"/"es" or "seiner"/"ihrer" in my view.
My main gripe is that the gender is a needless extra burden when learning the language, and it doesn't even make sense some times (my go to example is "das Mädchen"). Luckily German is not as bad as french in that part, which even changes words themselves based on what gender you are talking to!
Careful throwing those stones!
Besides that, there's a huge difference, since plurals have clear cut rules, while object genders are only by memory with qualified guessing. That said I would welcome "2 dog", although Japanese has other problems with counters (e.g. "yonko", "yottsu", "yonki" etc), so not a very compelling argument to make...