"We all know it is best, to turn breaker off at power pole before plugging shore power cord in/out"
We do? Power on first then add load is the usual rule. Note that after a power outage at the stick house area, the power company wants you to turn off your big appliances before their scheduled power back on time, so it won't be overloaded at start up.
With portable Honda EU3000, and near freezing out, before plugging in my 100 amp charger, I had to let the Honda warm up a little and also have it on full revs. If the Honda was still cold, its engine would conk out. That is not quite the same as popping its breaker from the electrical load. In that case, the engine keeps running as long as the Honda is warmed up a bit.
Once running a couple minutes, no problem with the 2800VA gen and the 1900 VA 100 amp charger.