They have been criticized for that, yes, but I think undeservedly so. Fundamentally, I just think it's pretty dumb how we allocate domains in the first place, and that this sort of thing should be seen as the natural consequence of allocating resources stupidly.
As for the other thing, I think front-running is a pretty different situation, and is bad for reasons that don't apply here. Although I believe most of the legend of that came in part from a misunderstanding of what was happening. Some registrars would put a hold on the domain you searched for, which would automatically be released after a day or two. Their rationale was that it was a bad experience to search for a domain, and then have it snapped out from under you during checkout. Of course, it also conveniently prevented you from buying the domain from a competitor, and I have no doubt that that was part of the motivation for doing it. I agree that that's a bad practice, but true front-running is much worse.
As for the other thing, I think front-running is a pretty different situation, and is bad for reasons that don't apply here. Although I believe most of the legend of that came in part from a misunderstanding of what was happening. Some registrars would put a hold on the domain you searched for, which would automatically be released after a day or two. Their rationale was that it was a bad experience to search for a domain, and then have it snapped out from under you during checkout. Of course, it also conveniently prevented you from buying the domain from a competitor, and I have no doubt that that was part of the motivation for doing it. I agree that that's a bad practice, but true front-running is much worse.