This isn't a reason to justify the tactic for the same reason the game isn't magically fair because each team has access to the same unbalanced kits.
I do it a lot on some maps and better than most and I would love to see it gone anyway. You can just repeat the same shots at the start each time because people take predictable paths (not like there's a lot of paths anyway). They're boring and easy to get hits.
I've deleted people at the start of rounds with 3 back to back hits even when they're specifically try to hide/avoid prefiring. Those people rightfully got frustrated and complained about it in chat.
Is this even releavant? I don't even know if this happens often in mcc because I doubt many contestants adopt this tactic from playing 9 rounds every month.
I honestly don't even see why anyone would be against some change for this. If there'd be a 1-2s delay on bow usage at the start of the game only prefiring would be affected. For the rest, the game is basically the same. At worst a person could be confused by the delay if it isn't communicated to them properly.
People wouldn't get frustrated from prefiring and the people who want to shoot still can once everyone's had a chance to spread out a bit.
The only argument against this I can see is if you want to get easy, low skill, shots against 4 players lumped into a small space.