It has zero to do with “the Vatican clerics”.

Generally a cause for sainthood is pursued by the diocese, order, or community. Many many Catholics have been martyred in WWII, Korea, Eastern Europe, the Soviet Union, China, Vietnam, and so on at the hands of enemies of the Church.

The Curia could not possibly consider all of these individuals and go through the extensive documentation necessary to consider their causes. It can be a very time-consuming and expensive process.

The Oklahoma City archdiocese funded Father Rother’s cause. So, let’s cut the “the Vatican clerics are pretending”. The individuals whose cause you wish promoted had both community and diocesan roots and that’s where the process should begin.

Apparently Pope Francis wishes to expand the definition to include those killed in odium caritatis” - “out of hatred for love” - which should make the process easier.