The reason is simple. To refute your assertion that it is the purpose of the Catholic Church and Catholics to minimize Christ.
In typical liberal fashion, the protestant projects onto the Catholic what they already practice. Christ, as understood by the Protestant is reduced to the Jesus + me relationship in which the Protestant plays the dominant role that sola scriptura allows them to do. Servants of Christ? No. Servants of themselves.
Having secured for themselves the authority to define Christian doctrine through the sola scriptura mechanism the Protestant can't countenance anything that threatens that. So, in effect, Christ is diminished to whatever comports with the carnal thinking of the Protestant. He's my Jesus, not yours. Ultimately its a selfish motivation which is not of God.
Name any Catholic doctrine you like. What's the constant Protestant refrain? "It takes away from Jesus." Please. If what the Protestant said was true and the Catholic Church and its doctrines stole glory away from Jesus, then he wouldn't be Jesus. To suggest that the created has subordinated the Creator is ludicrous. But that's the inevitable conclusion of the Protestant whose concerns are carnal and temporal in nature.
The Eucharist, the Marian doctrines, Papal Infallibility, etc. All of these things are Christ-centered. Jesus is not constrained by anti-Catholic prejudice. If anything is being taken away it is being taken from the Protestant. But in true Protestant fashion the refrain is, non serviam .
The Eucharist...Christ centered.
Marian doctrines...Mary centered...hence the name Marian doctrines.....
Papal infallibility....pope centered...hence the name papal.....you get the idea.