Or, more quantitatively, the Joyo Kanji has 364 simplified characters out of 2,136 (~17%) [1] while the mainland China simplified probably about 2,000 out of 7,000 common characters (~28%) [2].
It's 17% and 28%, but much, much higher for the most commonly used characters, which is where the divergence between simplified and traditional grows even more.
This divergence is not the biggest deal, but still big enough to refute the claim that Japanese is easier to learn because it's "non-simplified" (there may be other valid reasons though).
I didn't make that claim. Maybe your talking about another thread?
It's not that it's easier to learn, it's that the path of going Japanese -> Korean -> Chinese is the easier, most logical path. The diverging simplified Chinese standard characters being a large reason behind that.