I may disagree with your opinion, but I will give my life to defend your rights to express it.
No such defense necessary where Monzo are in charge. This is an open community available to everyone, including non-account holders.
What @anon23935806 said might be in effect for you because you’ve not actually posted much before. Any derogatory posts will be removed and duplicate topics get closed off in an effort to keep the forum as concise as possible, but generally on a day to day basis you probably won’t get censored for anything. You’re free to criticise Monzo, but be prepared to state your case clearly because they’ve got a lot of die hard fans.
May I suggest you study the community guidelines.