For it to be ethical it must be highly targeted and explicit. When it's not, in the real world it more often turns out to be a case of "lip service" or hedging. (Both of which are pretty close to hypocrisy ethically speaking.)

Just for an example-- Richard Stallman targeted his use of a proprietary compiler specifically to compile a free software compiler.

Another one was Lawrence Lessig starting a Super Pac to run for president with the singular goal of replacing dark money with publicly funded campaigns.

Yes, fair. I'm not talking about the signalling/optics side of it at all. If they're not trying to criminalize it then they're not trying to criminalize it, regardless of whether they succeed in convincing people otherwise.

> Richard Stallman targeted his use of a proprietary compiler specifically to compile a free software compiler.

A relevant example would be someone who is lobbying for mandatory disclosure of source code, but not providing source of their own software until legally required to.

> Another one was Lawrence Lessig starting a Super Pac to run for president with the singular goal of replacing dark money with publicly funded campaigns.

Yes, and my point is that it's not hypocritical to use dark money for that, since to abstain would weaken his position even if he's actually sincere. On the hand, from a PR/signalling perspective, abstaining from dark money is not a effective signal, because there's nothing actually stopping a campaign that intends to reneg on it's promises from sending the same signal, if it sees that that would benefit it. So insisting on ideological purity just disadvanges Lawrence-Lessig-like campaigns relative to openly malicious ones, without actually filtering out secretly malicious ones.

Too late to edit, but I wanted to clairify that I'm talking about strategicly wrong (less effective than something else they could be doing) rather than morally wrong (of negative effectiveness).