What is the reason for the اختلاف (disagreement/difference) between prominent scholars such as Al-Albani and Ibn Baz, and what did Al-Albani say in his book "Al-Radd Al-Mufhim"?

Scholars have always differed from one another. Al-Dhahabi reported Imam Ahmad as saying, "No one like Ishaq has crossed the bridge to Khurasan, even though he disagrees with us on some matters, for people have always differed from one another." The harsh words uttered by some of them against others should not be emulated or narrated; rather, they should be disregarded. For this reason, the Salaf established the rule: "The words of peers against one another are to be disregarded, not narrated." Ibn Abbas said, "Acquire knowledge wherever you find it, and do not accept the statements of jurists against one another, for they are envious of each other like goats in a pen." Al-Dhahabi said, "The words of peers against one another are not to be heeded, especially if it becomes clear to you that they stem from enmity, sectarianism, or envy."