Flying through known or forecast icing

As you said, the answer 'depends' on how risk averse you are.

Legally, the answer is, you cannot climb into icing conditions
(forecast or reported) no matter how thin the layer is.

In reality, you can use some judgement in the decision. Is the freezing
level above the MEA? It is icing rime or clear? How thin is the layer?

ATC is not traffic cops. Their job is to keep you separated from other
traffic. They don't care whether you have de-icing equipment or not, or
whether you are complying with all the other FARs.