The men received letters written by the executive committee of the North Islington Seniors Club advising them of the decision.
One letter read, "Your behaviour and actions in recent months have gone against the values of the club and therefore we are no longer able to maintain your membership.”
The letters are dated Oct. 30, three days after the municipal election. Mammoliti has held the ward since 1995.
Mike Siriani used to enjoy the club's summer picnics and bocce ball matches. Now, he says he's one of at least a dozen seniors who were kicked out of the club or prevented from joining at all.
He believes it's because he has not been a supporter of Coun. Mammoliti. "I was actually supporting another candidate,” he says. “I think that's the biggest part. I see no other reason."
The letters notifying the seniors they are banned were written by club president Rocco DiGiovanni and three other members of the executive. When contacted by phone, DiGiovanni told CBC's John Lancaster, "This has nothing to do with politics. I don't care who wins or loses."
He suggested they weren't welcome because they didn't attend enough club functions.
Mammoliti urged city to lease site
Siriani said a close friend was also one of the people recently kicked out of the club. "He was attending the club regularly. And what I understand is that we both were not on Mammoliti's election team."
All of those barred from the club who spoke to CBC said they also publicly supported other candidates.
In the past three years, city taxpayers have paid out about $45,000 in grants to the club and to maintain adjacent sports fields. The city leases the space at 145 Millwick Dr., near Islington and Steeles. The city's corporate logo is printed on the club's membership cards.
City documents show that in 2011, Coun. Mammoliti urged the city to lease the site so area seniors would have a place to gather and socialize.
Siriani is angry his property taxes still support a place where he's no longer welcome. "I am a taxpayer, and I don't think this is fair. And a lot of people I've talked to in the community don't feel this is fair either," he says.
Some area residents refer to the North Islington Seniors Club as "George's club." Several told CBC News the club held events supporting Mammoliti during the recent municipal election campaign. One of them was a barbecue where residents said they saw Mammoliti's election signs prominently displayed.
DiGiovanni said no such events took place.
Senior citizen Adrian Salvati says he tried to to pay the club's annual $15 fee, but he was denied membership. He also supported a rival candidate. He too estimates at least 12 seniors have been denied membership or had it cancelled recently.
"Our seniors are the most vulnerable individuals that we have in our society, especially in the winter months,” he said. “This gives them an opportunity to go out into the club, meet some friends, make some new friends.”
In an email response to CBC News questions, Mammoliti wrote: "The North Islington Seniors Club is a private group that has a permit to use a facility rented by the city. Any disputes or differences within the group are handled internally and have nothing to do with the city or myself."
Mammoliti suggested the men may have been banned "for their conduct and behaviour."