Taylor came on for the final 10 minutes of the match and smiled and applauded the Stadium of Light crowd on at least two occasions.
However, he was met with chants of 'Steven Taylor, we wish you were dead' among other unsavoury offerings from both sets of fans, including one from the away end referring to Jimmy Savile.
"I didn't know that. That would be poor, in very poor taste, if that's the case. I would be disappointed to have heard that," said O'Neill.
"It didn't figure in my team talk, but some of the players had passed comment about it.
"He's absolutely entitled to his opinion. I am delighted he made their bench."