That annoyance won't happen too often. Three main reasons:
A: You are joining a server that has a lot of players, they will disappear before you can drive to track.
B: Somebody's spamming chat and needs to be kicked from the server. If you see this, you can go to chat menu, click the player who's spamming and press "kick player". Spamming isn't allowed on any server, it's simply just harassing other players and should be shunned.
C: You've been practicing so long that a lot of players have joined. You see this while they load, if you're very quick you might see few of them when you get on track...
Only B is actually annoyance but i haven't seen a single spammer in last six months... I don't know if the line in PLR file that says someting like "load cars while on track" works, have tried but it didn't do anything. So this is very very small problem, if it doesn't happen often leave the chat on. In leagues it's mandatory, so it is in RD club racing (where chat is strictly prohibited in qualy and race sessions.. i know, i've got two warnings from this..)
EDIT: Looked closer at the pic, should've done that sooner.. Where does this happen? Offline/online, what mode if it happens offline only and the server if online. I have never seen this before. Clean install and delete my docs\simbin all PLR and controlsets (backup frst if necessary!).
If it's online, the server may send you these messages via some hack/mod. If that is the case, notify the server owners or choose a different server. The "allow chat in-car" was once in the menu, now it's in PLR file only.