I only read a summary but it sounds like the predicted writing of tautologies sprinkled with anti-Catholic jabs:
-anti-war passages and attacks Catholic just war theory
(Why this is a problem: It's fine to be against wars and for peace in practice, but in theory the idea of a "Just War" came from the right to individual self-defense, applied to the collective of the people. The encyclical - according to the summary I saw - suggested war was "always wrong". This would be an error, or it is a revolutionary change that the "pope" is trying to make to Catholicism)
from the doc: "it is important to reaffirm that the 'just war' theory, which has all too often been used to justify any kind of war, is now outdated."
-attacks colonialism without explaining why Christians created colonies
(Why this is a problem: Christians believed "savages" were in danger of eternal damnation and so were willing to go to strong lengths to spread the Gospel to non-Christians. So any of the worst things that happened under "colonialism" should be considered in light of the concern they had for people who they thought were at risk of damnation forever)
-brings up historical attitudes towards slavery to freshly try to make Catholicism look bad
(Why this is a problem: many people have already "apologized" for past wrongdoings. This is purely an attempt to "guilt trip")
Hoping more people wake up to how opposed these people are to Catholic beliefs and practices (a minority of us believe "Leo" is definitely not a Catholic pope because of these obvious attacks on Catholicism)