Jesus was more than a social activist, but not less than one. There are several places in the gospels where Jesus was a social activist. In particular, he healed those who were sick, he honored the poor, and he fought to change the social status of those who were marginalized.
Let me give two examples.
One of the most amazing things that Jesus did was to heal lepers. This was very significant, because lepers were the lowest on the social totem pole. They were considered unclean from the book of Leviticus. This meant that they were cut off from the people of God and God himself. So, when Jesus healed them, he was saying loudly and clearly that he has come to raise the status of people. This is precisely why he wanted these lepers to go show themselves to the high priest. In this way, they would be reintroduced into the people of God.
Here is another example. Right from the beginning of his ministry Jesus called for a year of Jubilee. This idea was rooted in the Old Testament or Hebrew Bible. The idea behind Jubilee was to cancel all debts. Debt cancellation is a huge social movement.
Here are the words of Luke 4:
“The Spirit of the Lord is on me, because he has anointed me to proclaim good news to the poor. He has sent me to proclaim freedom for the prisoners and recovery of sight for the blind, to set the oppressed free, 19 to proclaim the year of the Lord’s favor."
In light of these point, Jesus would be in favor of raising social status - i.e. helping the poor, canceling unjust debts, and bringing healthcare to those in need.