I've never read anything more wrong in my life, pyrotech will ALWAYS have more damage overall than arsenal just because of how many dots you are tossing around and you dont need to be turreting to do it.
pyro will **** arsenal 1v1 in any environment with LOS, being able to just pop out and keep dots / thermal detonator / rail shot on cooldown lets you roll over arsenal who is forced to land tracers.
also the burst in pyro requires much less setup than arsenal, arsenal needs 5 heat signatures stacked on a target and preferably 5 tracer locks on yourself, pyro just needs incendiary missile on someone
Pyro is an amazing spec and the damage it puts out just completely ***** on arsenals considering you dont need to be standing still to do it