If there is one thing that virtually anyone can tell you about Jesus, it's that he sided with the outcasts and the oppressed. He was on the outs with the Pharisees and he hung out with tax collectors and prostitutes and Samaritans.
Simplistically applied, many people tend to take this to mean that Jesus would clearly have approved of any cause which is scorned by the wider society. Of course, we all want to imagine that Jesus is on our side, and people often feel criticism keenly, so the end result often seems to be that people consider whatever causes they consider to be important to be those which are scorned by society, and thus which Jesus would approve of.
Thus, for instance, I recall my youth group leaders back in high school explaining to us that "if Jesus were alive today" (a phrase which bugged me nearly as much as our catechist's tendency to declare that various things would cause Jesus to "spin in his grave" if only he knew about them) he would be marching in the Gay Pride parades and in favor of environmental causes. Why? Well, he was on the side of outcasts, and those movements are the outcasts. Ask someone else, and you'd get the precise opposite: mainstream society accepts gay rights and green causes, but pro-lifers and those who support traditional marriage are "the outcasts".
The big problem here, I think, is the simplistic attempt to identify outcasts and then assign virtue to whatever it is that they are considered outcasts for. However, although it's noted in the gospels that Jesus was derided for spending time with tax collectors, prostitutes and Samaritans, it's key to note that his message did not consist of telling people they should all go out and be prostitutes and tax collectors.
I think, actually, that the meaning of the "outcasts" theme has been entirely missed. In the gospels, we find Jesus spending time with a wide variety of people. There are outcasts such as prostitutes and tax collectors (which it's at least mildly interesting to note were outcasts for two reasons: they were collaborators with unpopular Roman rule, and tax collecting was a highly profitable business described in modern analysis as "tax farming" in which tax collectors tried to take as much money as they could off people and got to keep the balance between what they collected and what people actually owed). There are "foreigners" such such as the Samaritan woman, the Roman centurion and various soldiers (who may have been foreigners or collaborators). And there members of the Jewish elite like the Rich Young Man who says he's followed all the laws of Moses but balks at giving away all that he has and following Christ, or like Joseph of Arimathea who convinced Pilot to turn over Jesus' body to the disciples and gave his tomb for Jesus' burial. And then there are just ordinary folks (fishermen, relatives, women from his home town, etc.) What united the followers of Jesus was not a status as members of "outcast" groups, but rather their willingness to follow his calls to repentance and to "come and follow me".
Jesus didn't spend time only with "outcasts" nor did he spend time with them only because they were outcasts, but he was starkly different from many of the establishment religious authorities in that he saw those who were considered outcasts as being worth taking his message to in the first place. What was radical about his spending time with outcasts was not that he advocated in favor of what made them outcasts (Up with prostitution! Up with tax collecting!) but that he ignored their outcast status and preached to all -- the elites, the outcasts, and the in between -- considering all people as capable of receiving his message and being saved through his sacrifice.
This is why a focus on "Jesus spent time with outcasts" can end up leading one astray. Jesus didn't come to pick out a group of "good people" or even "interesting people to hang out with" on the basis of their being outcasts. Rather, Jesus came to present a message. He presented it to everyone, outcast or not, and he challenged everyone: Come and follow me.