Johnson has explained why he blasted Warner and chairman of selectors George Bailey in an explosive column in The West Australian.
The former bowler concedes his relationship with Warner and fellow former teammate Bailey was already damaged but insists that was not solely why he wrote the article.
"People have touched on it, (that) there seems to be a personal side to it, which there is as well," the 42-year-old said on his Mitchell Johnson Cricket Show podcast with broadcaster Bharat Sundaresan.
"But when I've written my articles, I've always tried to do it in a way that I can back things up ... it is my opinion, it is only an opinion piece.
"This one was a difficult one to do ... when I wrote it, I knew it was probably going to get a bit of attention."
David Warner is keen to end his Test career in the SCG clash with Pakistan in January. (James Ross/AAP PHOTOS)
Sydneysider Warner has expressed a desire to finish his red-ball career at home when Australia face Pakistan at the SCG in the third and final Test of this summer's series.
He and Johnson played together for Australia for more than five years, including in the 2013-14 Ashes whitewash and 2015's ODI World Cup victory.
Johnson said he received a "quite personal" response to a column he wrote after Warner's wife Candice defended her husband's position in the Test team on Fox Sport's program, The Back Page.
"I tried to ring (Warner) to talk to him about it, which I've always been open about with the guys," Johnson said.
"It was never a personal thing then. Until that point.
"That is what prompted me to write the article, or part of it, as well. It's definitely a factor.
"Some of the things that he mentioned in that message, I won't say it because that's up to Dave to say if he wants to talk about it, (but) there was some stuff in there, which was extremely disappointing ... and pretty bad to be honest."
Johnson said he had received strong feedback from Bailey after publishing an article about emerging Western Australia quick Lance Morris.
Mitchell Johnson took exception to comments from Australia selector George Bailey (pictured). (Darren England/AAP PHOTOS)
In a press conference on Sunday, Bailey responded to Johnson's latest column, saying, "I've been sent little snippets of it - I hope he's OK".
Johnson took exception to Bailey's remarks.
The former left-arm tearaway has previously been open about his mental-health challenges.
"I'm fine. I'm not angry. I'm not jealous. I'm just writing a piece that I felt I needed to write," Johnson said.
"It's basically having a dig at someone's mental health and saying that I must have something going on, (that) a mental-health issue has made me say what I've said.
"It sort of tries to downplay the questions that I've asked in that article … It seems very childish from George, and condescending.''
Warner has yet to acknowledge Johnson's scathing criticism but the opener's manager James Erskine described the 73-Test bowling star "ignorant" and a "backseat driver".
"If he basically thinks three people did sandpaper-gate, then he should go to the moon for a holiday. I mean, it's just a joke," Erskine told SEN on Monday.
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