The Blackpool Supporters Association said Ince's position was "untenable" and that he had "damaged the reputation of the club" in an open letter on Monday to chairman Karl Oyston, who himself admitted the club are "on a horrendous run".
After Oyston dispensed with Ince and assistants Alex Rae and Steve Thompson on Tuesday, veteran midfielder Ferguson will take charge of training sessions in the short term and is odds-on to get the job full-time.
The BSA urged Oyston to take action after a 2-0 defeat to bottom side Barnsley on Saturday meant the Seasiders had lost nine of their last 10 games.
That came on top of a disciplinary record which saw five men sent off across successive defeats to Yeovil and Derby in early December and Ince given a five-game stadium ban in October after an expletive-laden rant at a fourth official at Bournemouth.
The letter read: "We believe that the position of the manager is untenable. Recent matches have brought about a points return of one point from a possible 27, plus an FA Cup defeat. There has been little evidence that this alarming run of results will be turned around in the near future.
"The current manager has damaged the reputation of the club. Blackpool fans are proud of their club but feel that the behaviour of Paul Ince, specifically with the incident at Bournemouth, has let them and the club down and is not appropriate for a manager in such a privileged position.
"The feeling that is most prevalent amongst Blackpool supporters is that Paul Ince, via his tactics, attitude and results has destroyed the morale of Blackpool fans up and down the country.
"Blackpool's season, and the short- to medium-term future of the club, is being put at risk by continuing down this path with the current manager."
Whether the letter was a factor in Oyston's decision is unclear but, hours before the sacking was announced, the chairman said: "It's pretty clear to anyone involved at the club that things aren't good.
"We are on a horrendous run and we need players.
"I've made it clear that we need to be given information by the manager in order to help him. If we don't get that information, then we are all done for and something has to give.
"The message is we can't carry on like this, otherwise we'll end up back in League One."