And if it were, it still wouldn't matter because the AGPLv3 source would have granted you a license to that too being a copyright license.
You need a copyright license to use the binary. You need a trademark license to use the trademark. See the firefox -> iceweasel kerfuffle
It sounds like people are saying that a company can have their trademarks used by downstream distributors of AGPLv3 software, if the license doesn't explicitly prevent that, which just seems wrong. The codebase license is not a license to other company IP
I also don't understand why an entity couldn't do a DCMA takedown based on a trademark violation.
But that's not what's going on here. If the source is unchanged, it's perfectly valid (and often done) to just point people upstream. That is providing the source. And the code used to build their snap is available*, and you can see all it does is repackage upstream's official package.
* https://github.com/snapcrafters/signal-desktop/blob/master/s...
AGPL v3 specifically allows authors to add trademark restrictions that become violating.
Don't follow the trademark clauses, lose your copyright license, that becomes a copyright violation, actionable under DMCA.
https://github.com/signalapp/Signal-Desktop/blob/main/LICENS...
[1] https://drewdevault.com/2021/09/27/Let-distros-do-their-job....
If unmodified binaries are redistributed, there is no trademark violation. It's nominative use, and simply not misleading the public because it's the genuine article. Any obstacle to redistribution must therefore come from the copyright licensing terms (if the binaries are available to the general public), or from an individual agreement with the original recipient of the binaries (so no direct free, public downloads even if the binaries are technically under an open-source license, and export compliance is a bit more difficult). Not sure which applies here, but it's not a trademark issue.