Maybe they aren't proudly saying it, mP.
Maybe they are humbly saying it... as in not wanting to deny Him, simply because some people will accuse them of being proud or arrogant or whatever.
Peace to you,
One can be humble and proud, they are describing different personal traits and qualities, they are not exclusive.
As for calling oneself a slave or a servant - why is this shameful? He served (and still does serve) us as well.
mP:Because it trivialises true slavery and the evils in the past, by pretending to be a slave when we all live relatively comfortable lives. It also corrupts the true meaning of the word a problem that xians have in many other cases. The word refers to a hard existance involving violence, pain, and sorrow where one serves under fear of death and violence. Most xians in our western world hardly share this and its dishonest to do so, because xians in our world are definitively not slaves. Most xians hardly spend any time working for jesus in any manner. Slavery in the past old world and time was not a part time vocation it was 24/7/365. Even if you do for example some charitable work here and there, thats not full time. Im not going to comment about believing, but for the puroses of this discussion, i will play along. Jesus did not serve us, if you believe he died for our sins, he gave us a gift. He did it out of his own freewill not because someone forced him. His earthly life was not that of a slave. So lets be accurate and faithful to the meaning of the word.