Radical self-acceptance is an excellent way to get out of the hard work of finding out what you, personally, find acceptable and what you do not, and attempting to make those who have made such a decision feel guilty for making engaging in radical self-change. That bitch who lost 100 pounds and keeps it off is suddenly morally and spiritually inferior to Jay because she wasn't willing to ignore all her own impulses for personal growth in favor of just giving up entirely and relinquishing all responsibility and self-control.
Life demands growth, and to grow one must engage in what the 12-steppers refer to as taking a "fearless moral inventory" of your life and deciding whether or not unfettered gluttony and inactivity is a brave activist stance or the end result of being a useless asshole. When you accept everything you do, if you assign sanctity for accepting everything you do, you can trick yourself into thinking that there is a larger moral purpose behind eating an entire cheesecake in one sitting, or licking a dirty dildo, or buying tons of fast fashion because you're bored, or refusing to move for seven years because someone once asked you to exercise, or spending extraordinary amounts of money on snacks because one time you peeled a carrot and cried and refuse to move the fuck on.
Such bullshit. In that realm of magical thinking, you can fuck children, eat puppies, slay the elderly on a whim and follow it all up with a staunch refusal to wipe your own ass because you practice radical self-acceptance and are working really hard to embrace the parts of you that are involved in pedophilia, that are involved in animal and elder abuse, and are covered in your own shit.