http://en.wikipedia.org/wiki/Hate_crimeHate crimes (also known as bias-motivated crimes) occur when a perpetrator targets a victim because of his or her perceived membership in a certain social group, usually defined by racial group, religion, sexual orientation, disability, class, ethnicity, nationality, age, gender, gender identity, or political affiliation.<1>
"Hate crime" generally refers to criminal acts which are seen to have been motivated by hatred of one or more of the listed conditions. Incidents may involve physical assault, damage to property, bullying, harassment, verbal abuse or insults, or offensive graffiti or letters.<2>
http://en.wikipedia.org/wiki/Social_groupA true group exhibits some degree of social cohesion and is more than a simple collection or aggregate of individuals, such as people waiting at a bus stop.
Characteristics shared by members of a group may include interests, values, ethnic or social background, and kinship ties. According to Paul Hare, the defining characteristic of a group is social interaction.<1>
...acting in "defense of others"? What others? Every pregnancy has a risk of a stillborn fetus. The murderer said some women "changed their minds (about getting an abortion)". This changing of their minds can take place anytime up until the abortion is actually performed. So the murderer was acting in defense of a probable "other". Can one act in defense of a probable "other"? Did the murderer conduct a medical exam of a woman about to get an abortion? Did the murderer establish the fetus was a viable fetus. Was the murderer qualified to make such a determination? Was Dr. Tiller about to perform an abortion on THAT woman?
The murderer had no knowledge of any of the Probable "others" or their medical condition (viability). He was acting categorically. He did not have any specific knowledge as to the viability of the fetus or of the woman's medical condition (whether there was a risk to her health from going to full term). He murdered Dr. Tiller based upon his previously providing a medical service which his patients wanted. The murderer was not acting to protect anybody. It was a categorical execution of Dr. Tiller based on Dr. Tiller's beliefs which differed from the murderer's. Last time I checked, you can't murder someone because of differences you have with them in beliefs.
The murder of Dr. Tiller was a hate crime.