SJW:s capable of filtering out their agenda are, practically by definition, not SJW:s.
One of the key aspects of good writing is about being able to see, feel, visualize, and transmit the thoughts and feelings of others. Good writing requires a level of empathy that is completely alien to the mindset of the average SJW. They genuinely do not understand how or why people may not agree with them; to them, it is inconceivable that others do not share their point of view, and they attribute all differences in pejorative terms, whether "ignorance" or (more commonly) malice.
Not only SJW:s do this, and it is very much dependent on subject matter. For example, most people writing anything at all dealing with "nazis" have never in their lives talked to any form of genuine fascist, and are completely ignorant in regards to their viewpoints or world-view, resulting in incredibly shallow characterizations, even outside of obvious popular propaganda.
SJW:s, however, differ in that they are supremely ignorant on a vast array of subjects while also being deeply opinionated on an equally vast number of topics, as well as lacking in any form of genuine empathy (or even a will to empathize, since this would by it's very nature challenge their by-design shallow world-view).
The maintenance of cognitive dissonance requires nurtured ignorance, and is a key component for manufacturing useful idiots for the purpose of cultural marxism and the enforcement of political correctness.