It might be that the parent poster took your use of "egg" as the sexual orientation meaning [1], instead of taking the metaphor more literally. It probably depends on the circles one lives in, words are often contextual.

The word was standing out a bit in your sentence, which made me wonder if that was the intended meaning for a sec. But I didn't quite get their post either, and now that I re-read it, the explanation I offered seems less plausible.

[1] As per https://www.urbandictionary.com/define.php?term=egg "Transgender person who hasn't come out yet"