Earlier quoted context omitted.
It's a legitimate concern, like having a spammy clickbait article. The site infringes on Github's trademarks all over the place. Can the site still get users' time and attention without stealing Github's branding?
When it's a tool that is explicitly built off of the Github platform, it doesn't seem unreasonable that they mention Github. If Github cares, let them file a C&D or just talk with the author--it isn't our job to play trademark police. It's entirely too negative a behavior on our part.
TMs are for consumers. It's entirely a consumers business to ensure that they are not being deceived as to the origin of goods and services they receive solicitations for. Yes GitHub should also be concerned but it's not their concern alone.
TMs benefit us in preventing financial incentive for scammers and frauds.
Expressing trademark concerns can be a positive thing, as here.
My initial view of the page had me assume that it came from the owners of Github™ as it used the name in the domain and used a [partial] GitHub [imitation] logo as a full viewport bg-image and mentions "on GitHub" in the most prominent page copy as if you're on GitHub.
I'd be surprised if there wasn't intent to use these elements to make the site appear to be "official".