I have no problem with this practice at all. Skipping bosses and as much trash as possible means better gear, faster.
What about the players in the team asking to kill all bosses since they can drop something they need?
This game is about progression. First you get gear from heroics, then you go to other like OP. But first you have to get there and wih all this boss skipping it will take ages.
If not be able to gear up in the first place what is the point of ths entire system? Bosses should not be able to be avoided. I dont care how many mobs we skil along the way but the bosses needs to be killed.
I would say it is outright rude not to respect someone in team needing a special boss and team members respond "sorry no time only runs this FP for comms".
Just let all the bosses be killed before the flashpoint can be completed, problem solved in many ways.
Next time you see someone write in chat that they need to kill the bosses, please listen.