There are two sides to every argument.
Just because you can do a thing it doesn't follow that you should do a thing. Simply because we can kill and eat lower species, does it necessarily follow that we should? When civilization was young that may have been the case, meat was required for survival. Now that simply isn't true, not in non-third world nations anyway. Science has created several alternative nutrient sources that provide for our dietary needs and several of the plants found in nature can provide the things our bodies need just as well as meat can.
So why has the habit of eating other living creatures persisted throughout history. Many point to the Bible and the Book of Genesis. God putting the animals on Earth for Adams use and all that. That argument only works if the person your arguing too is a Christian, and even then it can be argued that "use" does not have to imply consumption, so it's a flawed argument.
I have pointed out the fact that even if everyone stopped eating meat based on the "cruelty" factor we would be left with an overpopulation of domesticated stock. This would cause several problems like where to house them and who would care for and pay for the animals. The answer to those questions is actually not as complicated as it might seem. Rather than try to force meat out of the public consumptive pattern all at once, it would be better to shoot for a gradual end to meat consumption. While doing so, you gradually begin thinning the herds being kept by commercial farmers and begin preparing animal preserve space for the herds that will be left. This process would take several years, but would result in a manageable population.
Health concerns can be raised regarding the proteins found in meat and the calcium and other minerals found in dairy products. Again, a slow phasing out of the products now in place and implementation of replacement with substitutes already found in nature could be managed. The products are available and while they do not taste the same many of them do provide the same nutritional content with out the fat content or cholesterol found in traditional foods. Over time, these new sources would become the "norm" and future generations would look on meat consumption as odd, even unhealthy.
Do I think that our society is ready for such a change? Not right now. Our palates and our cultural senses are attuned to a certain way of doing things. Right now, being a vegetarian is outside the cultural norm. Do I think such a change could happen? Yes, actually I do. I believe that as a society progresses it will inevitably shift away from killing for any purpose. "Just because you can do a thing, it does not follow that you should do a thing." I think that within the next decade or so we will begin to see a slow melding of these two points, more vegetarian options will begin to appear...and more people will start to choose them.