The web sites you refer to are inaccurate and misleading. For example, they fail to inform the reader that papal encyclicals under the Ordinary Magisterium contain non-infallible teachings of popes. Thus, what is taught can be further clarified and reformed.
The encyclicals you refer to, such as Pope Pius’ ‘Quanta Cura’ (condemning modernist errors) of 8 December 1864, are documents of the pope’s ordinary magisterium. In this capacity the pope does not exercise his charism of doctrinal decision. A pope teaches infallibly only when he speaks ‘ex cathedra’ (from the chair of Peter) under the Extraordinary Magisterium. Encyclicals like the ones mentioned in your previous post are not ‘ex cathedra’ documents. There are only seven such papal documents in the history of the Church. And the teachings in these documents are irreformable and irrevocable: for instance, the Immaculate Conception of Mary.
Now the Holy Father does have the authority to speak in doctrinal matters without using his charism of infallibilty. And since what the pope teaches is non-infallible under the Ordinary Magisterium, there is room for further clarification and reform. The Code of Canon Law states explicitly that “nothing is understood to be declared or defined dogmatically unless this be manifestly certain,” and what is stated only in encyclicals under the OM is not manifestly and certainly defined as dogma.
But this is beside the point, since Pope Pius did not unqualifiably condemn all freedom of thought and expression. He targeted liberal theologians and thinkers who opposed the orthodox teachings of the Catholic Church. The same goes with the other instances you drew our attention to. One has to keep things in their proper context at a given period of time in history. I suggest you read Pope Pius’ encyclical yourself rather than accept the distorted views of anti-Catholics who deliberately try to misinform and mislead people. I don’t have time to treat all the other examples, but I hope you get the message.
PAX