Bad for Business #3: Admitting to fakery makes the wrestlers look weak.
If we analyze the exact words--profanity and all--that Ronda Rousey uttered, we can easily pinpoint the main reason why breaking kayfabe is bad for business:
“It wasn’t a promo they gave me other things to say I didn’t f***ing say it. It’s not a promo. It’s not an act. I’m not going out there and doing their f***ing act anymore, I’m going out there and doing whatever the hell I want. And they can explain it however they want, but f***em. Everybody. WWE Universe included. I meant that I’m going to disrespect the sport that they all love so much. ‘Ohhhh don’t break kayfabe Ronda!’ Wrestling is scripted. It’s made up. It’s not real. None of those b****** can f***ing touch me. The end.”
By stating that none of the women in the WWE can 'touch' her, Ronda Rousey is making them look like weak performers instead of tough competitors. While this may or may not be true--Becky Lynch grew up in Dublin's mean streets and could probably give Ronda a good fight at least--it does damage the reputation of the other wrestlers.
After all, you don't hear Robert Downey Jr. state that Josh Brolin is 'weak' and that Thanos cannot touch him!