I am not the right one who can judge someone/anyone.

[Hansman]

I know that in negative sentences, anyone is used and in positive sentences, someone is used and then, how about this one?

I am not the right one who can judge someone.
I am not the right one who can judge anyone.

I think that the first one with someone is natural and correct.

What do you native English speakers think?

 

[PeterCW]

Neither sentence is natural. I will leave comments on the grammar to qualified teachers.

I would say "I am not the right person to judge ...". I would be far more likely to use anyone or anybody but it would depend entirely on the context.

 

[5jj]

I know that in negative sentences, anyone is used and in positive sentences, someone is used and then, how about this one?

This is not a 'rule'.

Some is used if the idea is restricted or limited in some way.
Any is used if the idea is unrestricted or unlimited.
Any applies to all or none; some applies to part.

The restriction may be a real one - There's some cheese in the fridge - or a psychological one existing only in the mind of the speaker - Would you like something to eat?

Lewis, Michael, 1986. The English Verb. Hove: LTP

Lewis's words are true of some/any compounds with -body, -one -where, thing, ...

 

[Annabel Lee]

I am not the right one who can judge someone.
I am not the right one who can judge anyone.

I find both choices awkward in your sentence. You seem to be trying to say something like this:

It is not for me to judge others.