>>36144277He's honestly not wrong if you're someone returning to the games for the first time since gen 1.
There are now almost 1000 different Pokemon to know and collect. Even if you already know the original 151 pokemon that's still about another 850 ish to memorize from the bottom up.
Assuming you want to battle the least bit competitively, you must also memorize their typing, stat distribution, movesets, and abilities as well as the best items that work for that certain pokemon. And also assuming you aren't just hacking a team from scratch or using simulators, you are now have to learn about breeding and egg groups.
You honestly have less to remember from the periodic table.
