I think there is more to being the GOAT then picking up a grand slam. If someone comes along and wins four majors total, but they all happen to be in the same year, I don't think I'm going to put him above people who have reached double digits. If you would, then good for you.
The OP is only remembering better days. Murray's and Djoker's wins certainly count, but they don't change or take away what Federer has already been able to accomplish. Even if you will never admit that he is the best, you must certainly think he is at least very good, no?
I've said he's one of the best, but he's not the greatest. The OP is so ****ed off that his hero is being passed by his rivals--but a simple look at tennis history shows every generation of men faced the same issue. The difference here is that I do not recall fans of older generations being so hostile to other players' fans and/or defensive about a player being...outplayed, or passed by.