If you create a private shortlist then these messages should go away for any player on that private shortlist. The downside is you won't get news messages if someone else bids for them but since you check them regularly this probably won't be a big issue for you.
IMO it's a bit over the top but there are probably some who would argue that having 50 players on a shortlist is a bit over the top as well :p
Personally I've found these parts of FM to be like working with someone you can't stand who keeps nattering on about nothing. Eventually I tune them out and nod my head, along with the occasional grunt like sound as if to agree with what they are saying. And just like FM sometimes they'll actually be telling me something of relevance but it'll be in one ear and out the other.