He never told you to stop doing the mod, he just said that with the new season and its respective changes, the effort you'd have to put into modding a rather unmoddable game is too high to really pay off for you. You are right when you say there's people who will enjoy your mod, but it's a hell of a job doing a season mod all alone (if you want to do it properly) and it takes up a lot of time - which will make it hard for you to finish it before the release of F1 2014.Not to be rude or something but
I already knew you didnt liked the idea of this mod. It was a hard decision for me to stop with it and then agreeing with it, i find it not really at the place right now, but that's just my opinion
As I said, @TheJlfan didn't tell you to stop working on it, he was just expressing his opinion that it simply wasn't worth the effort.