If recommendations are mostly off-topic across Stack Exchange, how is that the site-rec exists?
Q: Recommend me a SE site where I can ask about X recommendation
A: None, recommendations are off-topic
Recommendations for an SE site are meta recommendations, and so are on topic here on meta.
Note that I am answering the question as edited to be about the meta tag, which is not what was originally asked.
Sorry about the excessive italics