Personally I see valid arguments against eating meat on Friday, but that is only because that argument is as valid if one picks any day out of the week to not eat meat. One could get the exact same benefits if they didn't eat meat at all, or if they picked Tuesday to not eat meat. But, I also see it as people's rights to pick and choose whether or not to eat meat on certain days or at all.
Some of the reasons to not eat meat: I see cost as the big factor. Others are to protest the inhumane treatments that the factory animals go through, because it is not safe (one could choose to only eat organic and/or kosher meat for the same reason), they wish to try vegetarian (or vegan) lifestyles part of the time (or all the time, as they personally decide), or for medical reasons. One might also choose to give up pork for health reasons or because they do not like the way the animals are treated.
However, to doctrinalize not eating meat is wrong. Even though I almost never eat pork (because I don't believe it's good for you), that doesn't mean I am going to bash someone else for eating it. Some people can and do eat lots of pork and not run into health issues for it. Others find equally valid reason to eat lots of red meat frequently--including that they have done so for their whole lives and are in better health than those who became vegetarians in their early 20s.
This is something each individual should decide for oneself--not for the church to decide. I can also think of quite a few things that the witlesses proudly shun that also should be up to each to decide for oneself--such as celebrating Christmas.