Absolutely, a business must do what it needs to do to keep the doors open, but please don't be an asshat about it by making a political statement out of your change in costs.
However, I wonder how many of these companies are just belly-aching and using the ACA as an excuse to jack up their overall profit. If the cost of providing healthcare for all your employees is that bad, shouldn't we be hearing of the economic apocalypse from all restaurant chains out there who employ minimum wage workers?
The ACA isn't going to jack up their profits. If Denny's (or any other chain) thought they could make more profit with higher prices, they'd have done it. That is capitalism, and unless you disagree that all of us are smarter than some of us when making decisions for all of us, it's the best system in the world.
There will be no economic apocalypse because all these restaurants are facing the same artificial new expense - well, except for those who can get waivers. What you'll see is a very slight decline in overall market coupled with more efficient chains becoming more profitable, less efficient chains becoming less profitable, and the least efficient going out of business. To the extent that some chains have the political connections to get waivers, those chains will prosper at the expense of others, but even that is no more than a temporary advantage. If servers and cooks can get equal pay and better benefits at chains without waivers, then the better servers and cooks will migrate away from the chains getting waivers. For fast food, this may even apply to managers - I'm not sure how many chains are currently providing less insurance coverage than Obamacare mandates - and otherwise probably breaks down, since most employees are probably too transient and unskilled to compete among employers. And it's certainly thrown off by our shitty economy, where people are more likely to keep a job in hand rather than pursue a possibly better one in the bush. But in general, for chains like Denny's that employ servers and cooks with some measure of skills, obtaining permission to provide lower benefits than your competitors will eventually lead to losing your better employees. Still worth it in the short term, obviously, as long as the economy stays bad.