I am not sure of the purpose for not bonding the neutral to ground. A 3-5K genny is plenty to run multiple pieces of equipment, and if you are using a drill with a grounded case that shorts hot to the case, you now have energized the genny with no path to trip OCPD.
There's an exception in the code which allows for portable/contractor generators under 5KW to
not require GFCI protection if they have a floated neutral. I think this was originally added to avoid GFCI nuisance tripping at work sites, but has since been adopted for all small portable generator situations. The second reason for the floated neutral (at least from my discussion with Honda tech support) was that if you used your little 2KW generator to power your entire house during a power outage via a transfer switch, then the house circuit panel would provide the G-N bond, and a second G-N bond inside the generator was a code violation. Of course, that secondary G-N bond would also trip any GFCI in the path during safe use. So while that's true, very few small generators are tied into a house circuit panel via a generator transfer switch. The flip side of this is that many contractor generators
OVER 5KW already have an internal bonded neutral, which makes it a code violation to tie it into your house panel via a transfer switch. Yikes!
This little bit of intel took me a long time to gather simply because of the confusing and incorrect use of words such as grounding, safety-ground, bonding, earth-grounding, etc... If you note, I use the term G-N-E bonding when discussing circuit panels because that's where the neutral bus, safety-ground bus, and ground-rod all come together physically and electrically (or at least they're SUPPOSED to).