Well, we've got Pokemon Gaming Central for topics (like those regarding PokeCheck) that deal with the games exclusively- Pokemon General only deals with discussion threads regarding the franchise as a whole. Like you said, it may be semantics, but PokeCheck has zero affiliations to the Pokemon anime, TCG, etc., so it doesn't really fit in Pokemon General. And unfortunately, since I only have access to moderator tools within Pokemon General, I couldn't move your question to PCG's or Trade Corner's Chit-Chat threads, so my next best option was closing your thread and redirecting you there in case you were still curious about PokeCheck.
And I'm sorry if the "CLOSED." tag bothered you. The reason I started adding that to locked threads was due to an issue with a past member complaining that they couldn't reply to a thread when it was clearly closed. So, for extra clarification, I add that to the end of my posts- it's not meant as disrespect to a topic or any subsequent replies.