It is acceptable.
The problem lies within the lottery odds. If they spread out the lottery more (like they did recently, but even more), then there wouldn't be a huge push for that last spot. I think the problem comes when you have fans cheering for the other team, and that would be eliminated if you have the bottom 5 teams equal odds, then the next five and so on.
This year is an anomaly as it is McDavid. We haven't seen this deliberate of tanking in years, most likey even if the odds stay the same we won't see it for more years into the future. It's a hot topic right now, but it's only a problem because of how much of an impact McDavid has right away and in the future.
As for the whole theory that "you should be tanking if you are mathematically out", I completely disagree. For those teams like Buffalo, Arizona, and Toronto tanking makes sense. You are stripping the franchise out in the off-season; players, coaches and GM's are most likely being replaced. If you are a team like Edmonton, Colorado, Philly, etc. and you start tanking after you are mathematically out what kind of message are you sending? You are basically saying that this player you are trying to get a chance to get is more important than the team who is busting their asses night in and night out. If you think that doesn't translate into a tarnished dressing room culture, spoiled fanbase, and stunted development then you are clearly not looking at things from a deeper than "on paper" basis.
A team that is battling night in and night out despite the math is developing and growing at a far more rapid rate than a team that takes 15 games off at the end of the season and gives up. You look at the complacency in Edmonton and try and say those years of having nothing to fight for hasn't taken a toll on some of the best prospects in the NHL.
just imho