Other thing is this, those people don't know how to read or understand their companion skills.
There are SKILLS when active that can slow down companion healing or DPS because the companion is trying to spam a paticualr skill and doesn't rotate through the other skills as much.
A prime example is Doc for Jedi Knight, you turn off his cryo freeze skill and he heals/shoots more because he's not trying to spam cryo every 3 seconds.
So they may actually see a rise in DPS, only because the single bladed weapon is "turning off" the skills that slow down the companion's raw DPS.
I agree with this. Turning off the AoE abilities, especially the ones with a channel, will yield much more consistently high companion DPS. AoE is good and all when used properly, but you can't expect the companion AI to be able to differentiate proper times for it.