IMHO, "in my humble opinion," "in my honest opinion," "in my holy opinion," "in my highest opinion," "in my hesitant opinion," are the most common definitions; others listed in acronymfinder.com.
Also "International Medical Health Organization."

Listed and defined, an initialism, Richard A. Spears, 2007, Dictionary of Anmerican Slang and Colloquial Expressions 4th ed., McGraw Hill.

When I see it appended to a message or comment, I read it as "MY BELIEF (YOURS IS WRONG !).
In other words, the comment can be ignored as ninnyhammer.