With all due respect to Sen. John McCain, no, but also in his defense those remarks were made before the heavy regulation of the sport began. MMA is as valid a sport as boxing, K1 or any other martial art competition, more so now then ever before. This is mostly due to Dana White's belief in accepting and seeking regulation for the UFC. Gone are the days of anything goes, no holds barred blood baths. Today there are strict rules, regulations and guidelines that govern fights. Fighters that break those rules are swiftly disciplined.
An excellent example of this is Renato "Babalu" Sobral. While engaged in a match during UFC 74 with David Heath he executed and anaconda choke which won him the fight. This is perfectly legal, acceptable and quite frankly expected in MMA. The problem though was that Sobral did not let go after winning the fight. Despite referee insistence he held the choke to the point of passing out his opponent. This action resulted in his release from the UFC and fining of half his purse for the fight.
Another example for regulation coming into play is the now famous Kimbo Slice incident. Anyone who follows the sport knows to what I am referring. A rival company to the UFC known as EliteXc had signed a fighter named Kimbo Slice. He had an internet following for being a tough street fighter. EliteXC spent a lot of time and money trying to promote slice as an unstoppable force. However, after watching his 1st fight it was quickly realized that this man was a terrible MMA fighter. To try and bring some legitimacy a fight was scheduled between Slice and a member of the UFC Hall of Fame Ken Shamrock. If Slice won, he would have beaten a former champ and MMA pioneer. If he lost, he lost to an excellent competitor. Unfortunately for Slice and Elite XC Shamrock received a cut above his left eye the day of the fight while training. The cut was neither serious nor dangerous as cuts go, but do to its placement and because of regulations shamrock was not allowed to fight. A replacement was found for Shamrock, Seth Petruzelli, who expediently knocked out Slice in 14 seconds and rang the death knell for the already struggling organization.
Now if MMA were truly human cockfighting, Shamrock would have fought. If it were the beginning of the sport there would have been no problems because MMA began as a tournament style competition where fighter fought 3 or 4 times in an evening. It is a completely different game now. A fighter is actually safer in MMA then in boxing, since there multiple ways of winning and no 10 count. Unlike I boxing that does have a ten count and allows a fighter to continue to receive punishment. In MMA the moment a fighter is not intelligently defending himself referees stop the fight, this makes MMA far safer then boxing. So if boxing is not considered human cockfighting why should MMA?