No on is disagreeing with you on the boundaries, it's just you can't decree it and make it so. Forcing someone to set boundaries before they are able to enforce them will be counterproductive in my estimation. That's the process, when the time is right they will do it. For some the time is never right and they never do it.
When others see people unable (or not yet ready) to enforce boundaries, they then advise not to set them.
When I see that, I teach and encourage them to learn how to set and enforce boundaries.
That's just me. I can be a curmudgeon/SOB, but I'd rather exhort and lift them up to a tougher stance, and at least TRY to get them faster results. And no, it's certainly not guaranteed.