Bot lane clown fiestas have nothing to do with bot lane towers lack of shielding
No team is 4 man or 5 man ganking bot lane BEFORE the game reaches the 5 minute mark. 5 minutes is like level 3 or 4. AFTER 5 minutes, all towers take the same amount of damage.
The only reason that the damage shield exists for mid and especially top lane towers BEFORE the 5 minute mark, and the reason that tower first gold exists is to provide incentives for LCS teams to not lane swap and 4 man push bot/top tower for the first 5-6 minutes of the game and have 0 interaction with each other, then switch back and take the alternate bot/top tower that is still up for the enemy team. which takes another 5-6 minutes. Which means that the game doesn't actually start until 13 minutes, with the first 12 being boring as hell to watch.
So , in short, tower damage reduction for the first 5 minutes only exists to stop LCS play from being boring AF to watch, but has NO actual effect in 95% of games as bot lane doesn't get ganked until the 8 minute mark, when teams are strong enough to dive, take the tower and dragon in the time it takes the other team to respawn and recover.
SO STOP USING IT AS AN EXCUSE