It's more like he has a crush on him + a sexual attraction (Yashiro mentions that Nanahara spies on him getting fucked in the office in earlier chapters).Nanahara admits himself that he would sleep with him if given the chance but that in the end he still likes women better.When he says he's in no position to criticize Doumeki I think he rather means that even though Yashiro is a reckless boss and very wild sexually he still respects and worships him to the point of putting himself in danger by trying to find who's behind the assassination attempt all by himself.So I guess it's more like him understanding how Doumeki could ever have such a deep commitment for Yashiro even though he himself doesn't love him romantically.
Nanahara says to Doumeki, he's in no position to criticise him - is he also half in love with the Boss himself? :]