See the thing you all forget about Keith and shiro is that they have known eachother for a very long time
Like yes they care about each other more than anybody else on the team but also they are very mean to each other
Shiro would not hold back on giving consequences because he knows Keith and he understands what Keith needs and that is direct communication of what he's done wrong
Keith is kinda rude to shiro because he knows shiro finds it very funny and Keith knows shiro needs to fucking relax
Shiro and Keith are always like lightly hitting eachother or wrestling (specifically Keith attacking shiro) play fighting essentially because Keith likes contact
So from the outside it looks like they have a strained relationship but actually it's healthier than most of the paladins relationships
Keith: anyone with a workin set a eyes can see that he ain't, dummy
Keith: can't believe you didn't save me, I guess ya hate me now
Keith: can't believe ya didn't see that comin
Shiro: *holding back laughter* yeah I was too busy saving your ass
Keith: *sigh and judgmental look* shoulda ended ya