But @actually did you complain to the store management? I completely agree that your examples of one rule for one and another for others, of not treating all customers the same and therefor taking it out on the next customer if one is rude or of ignoring customers isn't ok. In that situation, you complain to the management and if nothing changes you take your custom elsewhere.
If shops are being unrealistic with their expectations and rules and going far beyond guidelines, then they will change their ways if custom falls. If certain staff are rude to all customers; then all customers will eventually shop elsewhere.
But the examples here are very much about being asked to stand behind lines, about not wanting to follow the store arrow layout because you don't need all the aisles, about pushing past people in your way because you don't want to wait behind them and about not wanting to wait to be called forward to pay. Those examples are not the fault of the store staff; they are the fault of the virus.
Your examples are of behaviour that needs to be escalated because it's unsafe - anyone breaking SD rules risks the health of everyone they come into contact with. There's nothing wrong with complaining about it through the right channel - there's a lot wrong with mocking and name calling though - even if they did it first, or everyone else is doing it (which is happening an awful lot on this thread)
Also totally agree re the NHS staff, yet I still read comments from people complaining that the A&E receptionist had a mask on and asked them to stand back, or that midwives want to wear face masks when birthing and partners aren't allowed on post and ante natal wards and how unfair that is - so I guess they're getting a fair bit of backlash too.