Advice on how to squash growing toxic behaviors

It is becoming a thing at my company where senior and executive leadership are participating even promoting backdoor conversations regarding others only to put out passive-aggressive short-sighted statements about How things should or shouldn't be done.

Example, a direct report on my team sent an email to a few folks and asked them to review attached doc.. our c suite executive put a blast out on slack about how we don't do this and they'd rather have an email delivered in another way. How did this get around me and why is an executive getting involved in a low level squabble? Is this normal??

Additionally, this behavior is now a blocker when I've tried to promote or give deserving folks on my team raises.

For example, I've been recently told by HR when trying to give an employee a raise that they're denying my request because they've heard or been given examples where this person might not be great at all parts of her role. If I ask for examples of what they're speaking to, they can't/won't produce anything. When I've asked how I can support this person growing in their role and getting the raise, they offer no advice other than I need to be a stronger manager. If I continue to ask questions a complaint gets sent to my manager that I am being annoyed or distracting... is this normal?

I am feeling frustrating. This toxic that folks don't address issues directly with others and folks spend more time building cases against one another than performing meaningful work.

Is there anything I can do?!

#1, this is a situation where you can't talk to HR. You need to have lunch/coffee with someone in the C Suite (probably whichever executive sent the blast on Slack). You have to have a direct conversation with this person to figure out what's going on and why they don't like the people you are managing, because it sounds like HR is just covering in a vague way for the executive's real issue.Leaving the company is always an option too.
That sounds awful and abnormal.Where are you in terms of hierarchy? As a comment below says, you could try to have a direct convo with the senior management.I used to say you should stick it out and fight for what you believe is right in this case your colleague who you think deserves a raise etc but to be honest I also believe in picking your battle appropriately. Life is too short to be at places that are not respectful of their employees so if leaving is an option for you, I'd do that.
You are in a toxic work environment where lower level employees are being squeezed and scrutinized. It is best to begin looking for employment elsewhere.
These are toxic passive aggressive behaviors that are unfortunately tolerated in work cultures that breed internal competitiveness - when you pit one employee against another or have a forced rank strategy (as a means to eliminate 5 or 10% of staff, regardless of talent or true performance). Corporate cultures like this can be corrosive and unless executive teams call out this behavior - and thoughtfully & intentionally model different ways to manage, it's not a place to find long term value. Start looking would be my advice. And to share that with the colleague also.
To respond directly to the subject line of this post:It depends. If you are in a position of power (csuite or level below), it's your job to try to do something about toxic behavior. If you're in HR, it's also your job. If you're a consultant hired to assess and fix culture, it's your job. If you are anywhere else in the org, not only is it not in your job description but you don't have the power to make the changes.Toxic workplaces will change you before you change them.If you're in a role where you have the power, then the way you change culture is by working with the top. Culture starts at the top and flows down, I don't care how "flat" the org says it is. Feedback to the CEO or board is usually the starting point, ideally backed by data (low NPS scores, etc). Never have these conversations without concrete and specific evidence.If you don't have power, there's really not a lot you will be able to do (although you can work to create more leverage, which is a different story; so think about who has power who you have the ability to influence and who could apply pressure on your behalf, for example). Ultimately it sounds like they've brought on people into leadership with values that conflict with yours. HR just wants everyone to shut up and comply. Csuite doesn't seem emotionally intelligent enough to know when wading in makes it worse and thinks that publicly humiliating people is OK. Your call about how much time you want to give this company and its people.
Red flags! My advice is to leave.