Ours isn't hex, it's black and white pinwheel dot (also by Am Olean) but we used light gray grout and I LOVE it. If anything, I wish the grout were darker. I wanted to be able to see the tile pattern on the floor and also not have to worry about grout stains. We used white grout with our white subways on the walls because I don't care for the look of white subway tile with dark grout (just my opinion of course).

Very seldom do I like "white" grout, it just looks to stark to me, and to my eye it can sometimes detract rather than add to the composition of a tiled surface. Especially on a floor.

I usually recommend what you and NC have already written about, which is a light gray, or a silver grout, in place of white for locations where people think they want white.

My other recommendation is to at least consider the other extreme...a charcoal (dark dark gray, or "light black") or even a black grout. It really makes the white hex tile pop.

For practical purposes, light or even white grout is okay for a private upstairs bathroom floor that might only see sock-covered or bare feet. But I've had a few people over the years that want a light grout in a public downstairs bathroom, or in a foyer, or in a mudroom. Light grout in those rooms will discolor/stain quickly, and with so much grout with small hex/dot tiles, discolored traffic patterns appear the the grout rather quickly.

I'll show them a sample of dot with charcoal grout and it's a literal shock to them as to how nice it looks. The tile pattern pops, it really accentuates the light tile on the floor, and dirty grout is not a worry.

And as to sealing grout...well, it'll still get dirty.

Just my opinion.

I vote for the charcoal grout too. Even more so because you have some black tiles.
If you have sons, you know white grout may not stay white no matter how often you clean IYKWIM...