Quoting Just Ames:" My Son knows I will not sit and watch him flop around and act crazy. He is carried to his room in which ... [snip!] ... ever. He will sit on his bed and sob as if he got the spanking of his life but we do not spank him. He hates being isolated."
Doesn't that show you how detrimental it is and make you stop?! Knowing that a child's most basic innate need is for unconditional love and loving attention... so you use your parental love as a tool to manipulate behaviour by removing your love (as that is how young kids perceive it) to force him to do what you want (ie "behave" in a way you deem loveable and acceptable) so he stops. Wouldn't you rather look at the cause of his problem, teach him how to self regulate (with skills, rather than being feared out of it with forced isolation), and teach him how to deal with the problem in the first place that caused the overwhelming emotion (aka tantrum 'flip flopping and screaming'). I know it's more work than just shutting the door.. but surely for his emotional development and learning in general.. that's what our job as parents is?
I just get confused at going through the isolation and seeing the distress and why it works, and coming to the conclusion "this is the right thing to do". I get confused at people thinking this is successful and it being a happy stopping point and something to continue doing and even advise others on.