How can one disassociate from previously read e-books whose titles, authors' names, or publishing houses are not mentioned, knowing that they were harmful to the reader upon reading them?

It is permissible to read books published online without downloading or copying them, if their owners have published them or authorized their publication. As for downloading or copying copyrighted books, it is not permissible except with the permission of their owners, in preservation of their intellectual rights, unless the benefit is personal and limited to what is needed, and provided that it is not used as a means of earning income. And whoever undertakes this out of ignorance of the ruling bears no sin, but he is liable and must seek out the rights holders to seek their forgiveness or compensate them. If that is not possible, then he must give charity on their behalf equivalent to their rights.