It was a joke and yeah I agree with you. However, it should be noted that we've already been doing this for the past weeks. I don't think there is much more to learn in the Diddy matchup given how linear the character is.Time to learn the matchup properly and explore possible counters more.
As of now a handful of characters should be able to go even with Diddy, and maybe some even have favorable odds (looking forward to Pikachu and Megaman), but that perspective should not be absolute when in the end of the day Diddy's wins at high-level play are mostly based on his technical easiness coupled with generous rewards.
I don't think Diddy is an unstoppable force of non-sense, but in practice he still is the go-to safe bet to compete with and I'm eager to see people invest on new approaches rather than tunnel-vision the game this early. With that said, I'm quite glad my scene basically has no Diddy active.