It isn't and the person you replied to didn't claim it was. But there just simply is not much evidence that OP was using the term commercially.
The problem is that this way it seems like an impossible battle. Even if you get location data of stuff like downloads (which is not sth you normally get if for example one clones the repo anyway), you cannot prove the software is actually used, unless you use analytics in the software itself. This sounds important for FOSS in the EU.
I'll give you an example:
Linus Torvalds has a trademark on Linux. It's GPL, but there is plenty of evidence of commerce to support that trademark.
Here's the Linux Foundation's financial statement for instance:
https://www.linuxfoundation.org/hubfs/Reports/lf_ar24_121524...
> In 2024 we are forecasting revenues of over $292M. In 2024, the Linux Foundation is forecasting to spend nearly $300M supporting our mission
That's some pretty solid evidence of commerce.
If they had some invoices with that ™ commercial name I'd say it would be viewed differently
I could see the reason if there's no evidence of (constructive) work being done (so a clear indication of someone holding on the trademark, ie. squatting, IIRC).
Now, if I had a forward looking business spirit, I could perhaps conceive the idea on combining a hobby of mine with trademark squatting to masquerade it, so perhaps this isn't so strange after all.
It may seem weird if you're thinking about it from the perspective of a business owner trying to protect their brand. That's why a business would want one. But it isn't why they exist. The legal basis of trademarks isn't brand or business protection, but consumer protection.
The point of a trademark is to protect consumers from being fooled or misled. If there are no consumers, then there's nobody to protect.
The other company doesn't have consumer either with this name, so why should the trademark be revoked? And if it had, shouldn't it be guilty of trademark infringement?