Appreciate that you may have a target market that my company doesn’t meet, but a generic rejection providing no specifics whatsoever will always be perceived as slightly insulting; particularly when there is a sense that it could be based on a rather superficial interpretation of some trivial detail (like the lack of a website, for example).
What goes around, comes around, you have no idea how influential the individuals behind the companies you reject might be.
You ought to spend the time to explain politely why your services are unsuited to a prospective client.
Also - my iOS account was de-activated before I received any notification relating to my rejected application so all I knew was that I couldn’t log on “we are unable to authenticate your request”. This also creates a bad perception.