From Longman Dictionary of Contemporary Englishsplit hairssplit hairsARGUEto argue that there is a difference between two things, when the difference is really too small to be important This is just splitting hairs. → split
Examples from the Corpus
split hairs• But I don't want to split hairs.• Let's stop splitting hairs and get back to the main issue.• Batard is a little sweeter than Chevalier but perhaps that's splitting hairs; both these wines are excellent. 