[TF2] Why the Thermal Thruster isn't Allowed in Degroot Keep

Recently had a conversation about Degroot Keep balance, and one suggestion that got brought up was the idea of allowing the Thermal Thruster.
They didn't understand why, so I illustrated a example of a game of three Thermal Thruster Pyros capping A, B, and C in under 30 seconds. You could realistically remove another 7-8 seconds if everyone was a Thruster Pyro and all capped each point, in addition to optimized movement.
Map Used: steamcommunity.com/sharedfile...
Pyro, Medieval, Jetpack, Speedrun, In, Attacking, Team Fortress 2