Tribalism at work?

Is this something that is normal? We had 2 separate teams at work consolidate, and then split into 5 specialist groups based on services offered.
I'm in in a team lead position at work for one of the 5 teams, and am one of the few original members who stuck the merge out and always helped my supervisor out with organizational duties and making sure things get done. The team I was on before consolidating was a well oiled machine. I can sincerely say that it's the best team I ever worked with... but there were also 8 of us, not 28. Unfortunately, the supervisor I had for that team has recently retired and things have gone south fast.
2 of the supervisors who came in the 2nd half of the consolidation have a "do not talk to my staff" approach...or aka "stay in your own lane" and discourage any taking initiatives or people working things out on their own. Feels very much like micromanagement.
I think this contributes to a toxic environment because people get resentful that someone goes straight to the supervisors instead of them directly...as a lead and group veteran it makes me resentful because I can't even help someone without being questioned on what they wanted or getting my damned wrist slapped.
An example of what I mean: one particular team checks voicemails. The supervisor of that team went on vacation for 2 weeks. During that time there was a 3 day period where the voicemail was not checked at all by the team and customers escalated it to upper management complaining that they never heard back from their voicemail. The entire team looks bad in that situation , not just that particular group since our customers don't know we're separated into different support groups.
Management was not very happy, so to try to keep things moving smoothly I'd been keeping an eye on voicemails. I had to ask 2x in the past week for someone to check them before leaving for the day because they've sat for hours. The last time I did, someone emailed me directly complaining about leaving a VM and not being contacted and not being able to work because of the issue they were experiencing ... so about 2 minutes after asking the team to check on voicemails after getting that email, I got an email from the group's supervisor saying not to talk to the team and to go through her. Honestly, I felt very demoralized and unempowered. One of those people obviously went to her to complain.
She also brought it up complaining about it to others because I got asked by several people throughout the organization what happened and why she was so mad at me.
This is just one example and one recent situation... there have been countless issues and recurrences with the supervisors talking about "their" teams and trash talking other teams... even though we are all part of the overall team.
Hopefully that makes sense. I'd like to talk to our director about the current culture and toxic atmosphere but I fear that I am so close to it that I can't articulate it well...I don't want to sound like a bossy Bess or negative Nancy, or like a girl who just got her feelings hurt. I'm also not sure how we can repair and unite the teams...this whole thing is so far from any atmosphere I've ever worked in (always collaborative teams that had some hickups with staffing, but supervisors were always united and supported any direction another supervisor or lead worker gave). I left work in tears every day last week because of the BS going on there. It makes me wonder if it can be fixed, or if the best option is just to leave.

Thank you for reading this far and giving me a safe place to air the laundry and get some feedback! I'd also love to hear your similar experiences and anything you found helpful (or not).

That sounds like an awful environment to be stuck in. My heart goes out to you that your work has devolved into this. I don't really have any advice and have never been in this situation but I did want you to know that you were heard.

I hope someone with something useful to say comes along

I think you can articulate your concerns very clearly. I would do some preparation, take notes of specific concerns/events with dates so that you can use 'concrete' examples of how this change has negatively impacted on the customers and the team. If there are others who feel as you do, get together outside of work and discuss ways of addressing these concerns. It sounds like you have a VERY insecure supervisor/micromanagement is endemic and does not have positive results. I have worked in places this can be addressed, and others I have had to leave because the workplace became toxic and I did not feel up to a long term 'battle'. Also, check your job description, it may will back up your actions as a team member. Good luck!