Bystander effect. A scientifically proven phenomenon where when people are in groups, everyone assumes someone else will take action and so no one does.
I also think people forget that the TDs (and any official really) are one human among many and will not see everything. They may be in the office, or the bathroom, or walking between rings, or standing right there but their attention is being demanded by XYZ and they just didn’t see whatever the bystander saw.
Report it. Complaints of “I saw this Person doing XYZ abusive or illegal thing and no one did anything about it” carry much less impact if the person who saw it didn’t report to the available authorities.
(I’m not saying it didn’t happen, to be clear. I’m saying if everyone reported these things, we’d have more ammo to go after the governing body for failure to take action)