Main issue I have with it is when a person is in comp, it doesn’t work. Now I get for when there in a game, but why when they are in queue? It might be something having to do with how matchmaking works, but its still kinda dumb, since its the queue.
Can you please elaborate? Your post is worded badly and confusing.
I think they’re just asking why you can’t invite somebody to a group when they’re queued for comp.
As for an answer, I believe it’s just to prevent the very slim chance of being invited to a group the split second one gets a game and receiving -50sr and a ban.
As an interesting side note: I was once in a 5 stack as a person over 1ksr above the lowest sr person but we had an unranked person in the stack which somehow let us queue together. The unranked person left the group the exact second we got a game and our now-four-stack was put into a game together that we never technically should’ve been 
. It seemed pretty buggy, so inviting somebody in queue could be pretty dodgy too.