A Facebook account posted by an audience member said Morgan's stand-up performance was full of homophobic references. The Ryman issued its own apology afterward for Morgan's behavior.
Morgan's outbursts triggered heated comment on Twitter, making him a "trending" topic Thursday and Friday.
Meanwhile, the Gay & Lesbian Alliance Against Defamation called on Morgan to remove anti-gay remarks from his show "and send a strong message that anti-gay violence is not something to joke about."
The Human Rights Campaign said apologizing wasn't enough. The gay civil rights organization it said Morgan "now has a responsibility to make amends for his horribly hurtful and dangerous `comedy' routine."
In his statement, Morgan, who has three sons, denied being a hateful person and acknowledged that "even in a comedy club" what he said went too far "and was not funny in any context."