Kearney is among many prominent people and groups, including Fremantle captain Alex Pearce and West Coast, to have strongly supported the former Eagle.
Brown revealed on Wednesday he is bisexual - the first current or former AFL player to do so.
While the last week has been an emotional rollercoaster for Kearney and many other people in the game, the eight-time AFLW All-Australian said Rankine's ban for his homophopic slur had shone a fierce light on the issue.
"There are a lot of conversations that happen as a result. Mitch Brown coming out as bisexual, it's no coincidence, the timing of this," Kearney told AAP.
"The commentary around it - although it's been a negative and it's been hard on the queer community, it can sometimes have a positive impact in terms of how we further educate players, and just the general community as well.
"Because the whole process (around Rankine's ban) stretched out for about a week, there was so much of this running commentary around it - how we can make the AFL a safer place for athletes to be their true selves.
"The fact there have been no 'out' players as well, that helps with the decision of Mitch Brown to then be able to come out and announce he's bisexual."
Kearney said her immediate reaction when she heard the news about Brown was to feel "happy", but it was also a reminder about coming out to her parents.
Even though Kearney never had any doubt that she would be loved and supported, there was still an element of anxiety.
"Everyone's coming out story is really unique - some are always easier than others, but it's always challenging," she said.
"It's really pleasing that he has a network around him, that he knows he'll be supported."
The AFL's homophobia is in stark contrast to the AFLW, where players such as Kearney are comfortable with their sexuality.
"The AFLW has always set a really good example of what true inclusion is," she said.
"It doesn't matter what your sexual orientation is, you're always welcome in the game.
"Gay men are seen to be non-masculine, but when you play sport as a male, it's very masculine.
"You don't quite fit the mould, which in itself is very tricky."
Pearce called Brown "courageous", while the Eagles likewise posted "we love you Mitch".
AFL chief executive Andrew Dillon called it "an important moment for him, and for our entire game. Today is a step forward."
AFL Players' Association president and Collingwood captain Darcy Moore applauded "Mitch's courage and candour in sharing his identity."Stories like his have so much to teach us as an industry if we are willing to learn."To any young people in the LGBTIQA+ community out there who dream of playing in the AFL or AFLW, you deserve a safer and more respectful industry. As the AFLPA, we are committed to working towards that."