All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallahu ‘alayhi wa sallam, is His Slave and Messenger.
There is no doubt that modern publication media include the beneficial and the harmful. It is permissible to benefit of the good and beneficial and avoid the harmful and prohibited. You may read, download, buy, and keep useful books as long as they are about lawful matters. Benefiting from useful books and other lawful resources is not forbidden merely because they are found on websites that also promote what is harmful and prohibited. Truth should not be forsaken because it exists alongside falsehood.
The well-versed scholar ‘Izz Ad-Deen ibn ‘Abd As-Salaam wrote, "Attainable truth must not be abandoned due to the accompanying falsehood." [Qawaa‘id Al-Ahkaam fi Masaalih Al-Anaam]
So read, download, and post what is useful, but avoid what is prohibited.
Allah knows best.