It's possible to get them off.
This is done in fpv builds. It's better to direct solder the motor wires to the esc.
Get flux and decent quality solder, I use a flux pen, you can get them off amazon.
You need a big enough tip to heat all the pins of each at the same time.
It looks like three per connector? Or 6 pin?
Put some flu. On the pins and apply heat with a bit of solder, when you see the solder flow pull the plastic part and it should remove.