Gareth Thomas warned Billy Vunipola only a 'heartfelt apology' for his support of a homophobic social media post from Israel Folau can stop rugby's boo-boys.
Vunipola has received formal warnings from Saracens and the Rugby Football Union in the past week after he posted on social media that "man was made for woman to procreate".
He also liked a social media post from controversial Australian star Folau that stated "hell awaits" for homosexuals, refusing to delete it.
Vunipola was booed and rainbow flag were visible among the crowd in Coventry's Ricoh Arena as his side made it through to the final of the Champions Cup in beating Munster.
One supporter even made his way onto the pitch post-match to confront Vunipola. A picture of the incident showed Vunipola being approached by a man wearing a Munster shirt, gesturing at him with his fingers as the former Pontypool schoolboy joined team-mates on a lap of honour.
Vunipola, meanwhile, said there was "no intention to hurt anyone" following his social media post and support for Folau.
He said: "Behind closed doors I felt a lot of love, a lot of kindness shown to me. I am just very grateful to be part of this team. From my point of view, I believe in what I believe in."
Thomas, was in Dublin on Sunday as a pundit for Channel 4, as the French side took on defending champions Leinster in the other semi-final.
Asked if he thought Vunipola's reply was an unacceptable response, Thomas, who was the victim of a homophobic attack last year , said: "Unbelievably unacceptable.
"I think for him to apologise and the club to make a statement, it's a very easy thing to say sorry, it's very difficult to mean it.
"Billy, even though he's not defending his own words, his beliefs in those words haven't changed even though he's made an apology.
"So for me nothing really has changed in Billy Vunipola's views.
"I felt a huge amount of sympathy towards Israel Folau in a sad way that it was such an uneducated response.
"What he's said about being gay is almost a choice, is very uneducated.
"Because I can tell you as a gay man myself, what I've been through in my life, if there was a choice, then probably at times I probably would have decided not to have been gay.
"Seeing Billy's like and comment on it and then what I feel is a pretty feeble apology by Saracens. I've never been told by anyone to go to hell in a very loving way. To me even the apology really doesn't cut it.
"You've seen the reaction that he's going to get and that could become quite regular for him if he doesn't make, what I feel should be, a heartfelt apology."
Nigel Owens delivers verdict on Israel Folau homophobia row in national radio interview
