The 20-year-old forward impressed for the Three Lions over the international break as he started, and scored, against both Spain and Switzerland.
That led to questions over whether Mourinho was making the most of Rashford's abilities as he has struggled to hold down a regular place in the United side where he faces stiff competition from Romelu Lukaku, Alexis Sanchez and Anthony Martial.
Rashford will definitely be missing when Mourinho's men travel to Watford on Saturday, though, as he begins a three-match ban after being sent-off against Burnley before the international break.
"I think I can expect that Sunday I'm going to be highly criticised for not playing him tomorrow because some of the boys are really obsessed with me and, some of them, they have I think a problem with some compulsive lies," said Mourinho.
The Portuguese coach then reeled off a stream of statistics detailing Rashford's 105 appearances in Mourinho's first two seasons in charge before pointedly suggesting other managers should be quizzed for their use of young English players.
"Marcus Rashford is not (Liverpool forward) Dominic Solanke, he's not (Chelsea midfielder) Ruben Loftus-Cheek, he's not (Everton striker) Dominic Calvert-Lewin.
"He's Marcus Rashford, Manchester United player, with an incredible number of appearances and an incredible number of minutes played at the highest level in the best possible competitions."
Mourinho has faced stinging criticism in the first few weeks of the season after defeats to Brighton and Tottenham saw the Red Devils lose ground on title rivals Liverpool, Chelsea, Spurs and Manchester City.
But despite righting the ship at Burnley and a two-week international break to ease the pressure, Mourinho again took aim at the press.
"The ones that wake up in the morning and the first thing that comes into their mind is Jose Mourinho and Manchester United, I feel sorry for them because there are much more interesting things to wake up and to be happy (about) in the morning than to speak immediately about us and about football.
"But for the Manchester United supporters, I think it is important they have the right idea of how things are in reality."
Mourinho also confirmed left-back Luke Shaw could return to action at Vicarage Road just a week after suffering a concussion in England's Nations League loss to Spain.
"Contrary to some news, to some opinions, by the protocol point of view and according to our doctor, he will be free to play," added Mourinho.
"The only situation we have to analyse is if you are going to play him when during the week he was not training with the team."