Felidar Sovereign too strong in B3

Had a b3 game where I had a t2 sol ring that led into a turn 5 Felidar Sovereign (6 cmc white creature that says you win the game at your upkeep if you have 40 or more life). I played it at 45 life and then it went around the table with nobody having any interaction or attacking me, where I won on my upkeep on turn 6. The table started to complain that its not b3 because they didn't get to all play 6 turns.

It felt a bit weird for them to say these things after spending the first 6 turns setting up value enchantments and ramp. Clearly the rules state that you can win before turn 7 and it can be b3, as long as it is not consistent. If you can't win vs afk opponents before turn 7, isn't the best strategy in b3 just to intentionally only play ramp + value enchantments to setup then pop off on turn 7 with cascades or extra triggers? It feels like that's more abusive of the bracket rules than winning before turn 7 occasionally.