Usually when people are sorry for nothing is that a sign that you need to leave them alone?

Not necessarily, it depends on you.
For me this would be a red flag and I would leave them alone (actually, I do leave them alone). Because other than lowering their value the most they can, I picture how they are very sensitive and maybe would need to receive apologies the same in many situations, to address their vulnerability fully. Also, I'd picture they are needy, and that they need constant reassurement they are doing good and that you're not abandoning them.
These are traits I cannot endure, I did that in my teenage in one relationship but that was hell, and I had similar traits from 2 other partners later. I'm never going in a situation like that anymore in my life, not even remotely similar. So for me that is a huge "no".
But other women might instead tolerate neediness better and are less blunt than me, and more attentive to the sensibility of others, willing to spend that extra attention for them. Some women might not find it like a scary trait to deal with, then.
So it depends on you for the most.
Depends on context. If it's something that only affects them then I think you're good. However, if it affects others then they're an asshole and you should leave.
Being unapologetically nerdy? fine. Unapologetically stepping on others to get ahead? Asshole.
Personally, I wouldn't throw a red flag n leave unless it was a detrement to others.
In my experience, it's a habit that developed as a result of making many mistakes and having to apologize for it. I wouldn't day that I'd leave a person alone solely due to this but I'd keep this in the back of my mind in case other signs start to show themselves.
Opinion
5Opinion
Maybe they have less confidence and hence they apologize more than what is needed for.
I repeatedly say sorry to the point of annoying others. It comes from childhood trauma and horrible adulthood.
Yes, but only if they SHOULD be sorry. The question is should they be sorry for what you think they should be sorry for.
No...
insecurity
Superb Opinion