I think everyone can understand, though perhaps not like, the supply chain issue. What frustrates people is the manner in which Tesla has been communicating this issue.
1) The process itself is a bit unintuitive. Not everyone would understand why a car would be shipped without an essential part, or at least why an incomplete car would be assigned to someone without any warning or clear impact on the EDD.
2) The original story I received was that the car was simply stuck at the regional distribution center and would be available to me as soon as they could secure a truck to deliver it. So, to find out that you still couldn't pick up the car even after it was available at the delivery site, really stunk.
3) When they admitted the charge port issue, they outright told me the part was shipped and even gave me a window for when to expect it. So either that was wrong, or there's something else going on. But a customer shouldn't fear blaming Tesla in this case if they were told Tesla had the issue under control.
4) It's not necessarily obvious that the EDD on the app isn't rooted in any sort of intelligence. As such, if you hear about the charge port issue on May 13, and see May 13-17 in the app, you assume the part is just about ready to install. It takes a few days and angry phone calls to see that it's just an automated Today + 4 pattern that has no connection to what's really going on.
5) Tesla can't control external supply chain shortages, but it would be nice to see Tesla exercising anything it can do. Or at least communicating why a seemingly workable option (such as re-allocating those affected by the ECU issue to VINs that will definitely be available imminently, after all, we're supposed to be next in line!) would be impossible. People here have had some good counters to why Tesla can't just stop everything to take care of a small batch of customers, but that would mean so much more coming directly from Tesla -- with some alternative proposals or make-goods (opportunity to change some specs for a canceled car that's ready for pickup, some FSD or Supercharger credit for when the car arrives, etc). Basically, something that lets you know that Tesla is actually empathetic to what customers are going through, and actually doing everything it can to remedy.