Proclaim Change From a Safe Distance

Though there a growing need for change being felt throughout the Church at the time John Colet gave his sermon at St. Paul's, Lutheran had not yet shook the foundations with his reformation movement. I don't know a lot of the context behind why Dr. Colet was asked to speak to the Fathers of the Church. Maybe one of the Cardinals saw need for change and asked Dr. Colet to speak on the matter, or maybe he took it upon himself. Either way, he did so from a safe distance. Imagine an Elder's quorum president who stands up in front of his quorum and say something like this:

"Elders, we need to be more virtuous. We need to strive to be worthy of the Spirit always. Let's all work on paying closer attention to the media we watch and participate in."

This is essentially what Colet did. Now, imagine an Elder's quorum president in the same situation who says this:

"Elder's, we need to be more virtuous. No more watching The Office. No more playing Halo. No more watching movies with any violence or sexual content like Lord of the Rings, or A Fault in Our Stars. No more loud music."

This is essentially what Luther did. In the first instance this is taking a very safe approach. No one feels attacked. Everyone agrees, because these are things they've heard all their lives and read in the scriptures. They can then take the message and use it (or likely disregard it) however they like.

The second example is a lot more dangerous. This causes hurt feelings, which often leads to retaliation. Or is some cases may lead to actual change.

(I only use the above media as examples of potentially popular media. I do not mean to give an opinion that any of them are right or wrong, good or bad.)
It seems to me Colet was not really trying to spark actual change, but instead, understanding his audience, preached in generalities of improving and trying to be better.