Self-hate is okay sometimes
I think that self-love and self-compassion are generally good, but there’s a right tool for the right job, and those are not right tools when the job involves a short-term endeavor that includes sacrifice and discipline.
In other words, you should live a life of self-love, but you should not expect self-love to give you any results when you’re trying to force a change. Being a little bit angry with yourself, having a negative self-talk, these things have a bad reputation, and rightly so if you live like that. But if you spend some months like that, maybe a year, and this kind of anger shapes you into a better version of yourself, then it worked and it was fine.
Self-acceptance is good if the thing you’re accepting is good, but what if it’s not? What if you are objectively not good on any given metric? What if you’re morbidly obese? Should you practice self-love and acceptance? Maybe. Maybe you should try it and see what this mindset does when you falter and miss your diet goals. “Oh, you had a rough day, you’re ill, it’s fine if you eat these five hamburgers. After all, look at all the progress you made!” What kind of behavior will this reaction support in the future?
Self-hate or self-criticism or self-anger have a bad reputation purely on the basis that they are negative, which somehow by default means that they are not good in any way, shape or form. Since when does “negative” mean “bad”? I can give you a ton of examples of bad things that are “positive” in their mindset/vibe. By extension, just because something or someone is negative, does not automatically presuppose that it’s the wrong mindset to be in.
Right tool for the right job. Sometimes you owe it to yourself and to others to display appropriate amounts of hostility towards some aspect of you. Ultimately it does come from self-love, I guess, because the opposite of love is not hate but indifference. If you hate some aspect of yourself, that means that you care, and anger is, if anything, a high-powered tool that can be turned against anything. Self-acceptance is soft and gentle, and self-anger is hard and fuming. Guess which of the two tools is better to apply in short bursts to shape something?