I think it is fine for MDG to be proactive in this space if they want to be.
It will come across as pushy to some, but other people might find it helpful if they aren’t in the scene and haven’t caught on to what Galaxy is.
You’re sounding worried that they are stepping on your feet - but I think all you need to do is explain your solution and why you aren’t using Galaxy. If you’re using Modulus, DO, NodeChef or whatever. I am sure you’re more than capable of explaining to your client why you chose what you went with…
I agree with Max and the others who said it is a little uncouth to beat down a competitor in that sort of marketing. They are trying to hit a trigger with the reader, but a happy Modulus customer will think that you’re just pissing in their pocket.