Let me help you there. Have you considered writing: "I think this lecture series is overrated, because $SERIES_A and $SERIES_B is much better, because ..."

Or you could explain why you dislike the communication style, the pace or anything else that others could also relate to.

This way we can just guess, and guessing includes bad options like "dev_0 just had a petty conflict with the lecturer" or "dev_0 tried themselves to teach this and did worse so it is envy".

So if you want to provide value, please explain yourself or just don't comment with one word in the future. If you don't want to provide value, consider commenting on youtube instead.