Wild speculation follows, or, “remember that I’m just making this stuff up”:
One possible reason I’ve come up with is that maybe it’s more consistent to be engraving a fresh clean surface. This rings a bit true because of their emphasis on PG and wanting engraving to be consistent and easy for all users.
It seems to me that engraving “down” would mean an added variable, as now you have to plow through an unknown amount of gunk, which presumably would be variable based on material and settings.
Other thoughts. AKA even wilder speculation:
Adding a reverse option may run afoul of an overall directive [which may or may not exist] to keep the ui and process simple? Too many fiddly bits is daunting to new or less tech-savvy users.
It may also be more fire-prone to do so?
May also have smellier or more hazardous gasses?
May also lead to a dirtier machine, especially lenses and other head components?
May also “double polymerize” (yes I know not a thing but you get my point maybe) the gunk resulting in a leading edge of supergoo that’s even harder to remove? Think of it like cooking candy, if you cook the sugar too hard it goes from sticky to rock solid.
It may be really hard to change the order based on how they’ve architected the software? Seems simple enough from the outside; may be a nightmare once you know what’s under the hood.
I suppose it all comes down to trusting that the people at GF are smart and acting in the users’ (all of us, of all abilities and needs) best interests. I think there’s tons of evidence of that, it may be frustrating sometimes but these are crazy good machines with overall excellent software.
That being said, please let us reverse the engrave. it’ll probably come with its own downsides but we may be able to work around them.