If you were fired for discussing working conditions privately with employees doing the same job you are doing, that would be a NLRB issue. For example, a group of line factory workers getting together on their own time to talk about ways to bargain for better working conditions would be protected. But that's not the sort of thing going on here. Your employer taking exception to the attitude you've shown him/her about how the manager runs meetings is not. Nothing about what you wrote is an unfair labor practice under the National Labor Relations Act (NLRA) and certainly won't get you your job back.
I suggest you focus on finding a job with a new employer rather than getting rehired by the old. Your quest here to find some violation of the employer to pursue isn't going to get you rehired. What it will do is further alienate you from that employer.

