Japanese is "hard" to learn because it's not widely spoken as much as languages like French or Spanish or English. It's used on one archipelago. This means that, for the most part, to be around Japanese, you mostly have to be in Japan. Japan isn't the only language with this problem, so stop playing.
Another issue is Japan's education system. In post-war Japan, they ratified ways to learn kanji. They opted for a slower method that stretched kanji over the course of 12 school years. They learn it by doing it over and over. And that method is fine...for children. This method makes it harder to learn when one is an adult, though, because that's not how adults learn. Our brains are literally wired to think and learn differently. English is another language like that because we have specific sounds and movements that aren't used in other languages, which makes it harder for non-native speakers to use. In any case, this doesn't mean learning Japanese is the hardest language as an adult. It just means that the method of TEACHING and LEARNING Japanese ought to change when learning as an adult. But Japanese people teach non-Japanese speakers how THEY learned how to learn the language. Which makes it harder on non-natives by default, because again, they're adults. However, alternative methods have shown to teach Japanese at a highly fast rate to the point of gaining intermediate level mastery within a year.
You literally don't know what you're talking about. Japanese grammar is easy. Kana is easy.
http://www.fluentin3months.com/easy-japanese/As for your English comment, you're wrong about that completely. There are also numerous Chinese who are opting to learn Japanese, and vice versa. Never mind the fact that English is the current international language standard and MOST nations opt to learn English, so this isn't even unique to the Japanese.
If there's a language you speak it would definitely be Opinionated Yet Uninformed-ese.