Is it judging when...?

I guess it depends on what your reasons are for being vegan. If you are vegan because you feel it's a healthier lifestyle, that's one thing. But if you choose to be a vegan because you feel that the way animals are treated for human benefit is cruel, then I would say you are sending conflicting messages. Even if you bought leather products before you became vegan, wearing them makes the statement that you condone animals being killed for human consumption (whether it's meat or something else). I'm not saying it's easy to uphold your principles consistently, or that it's even practical.