Superficial matters are not to divide us.
‘As for the one who is weak in faith, welcome him, but not to quarrel over opinions. ‘ Romans 14:1
Paul goes on in the rest of the chapters to specify some examples of what those opinions would be including diets and special days. This is how we reconcile the mixed messages the Bible has about passing judgment. Some matters pertain to judgment and others pertain to objective morality.
The “Only God can judge me” mantra can only rarely be used in the Christian’s life. Christians are required to judge other Christians if they are engaging in behavior that is clearly forbidden by God or have beliefs that are contrary to what the Bible teaches.