All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Indeed, you did well by advising your brothers, but we would like to admonish you to choose a good way in doing so, Allaah Says (what means): {Invite to the way of your Lord with wisdom and good instruction, and argue with them in a way that is best.}[Quran 16:125]
However, it is better to combine between At-Targheeb [encouraging people to do good by mentioning Allaah’s promises and rewards] and At-Tarheeb [warning people from evil by mentioning Allaah’s threats and punishments] and it is acceptable to focus more on At-Tarheeb when necessary.
As regards a person who is misguided despite having religious knowledge, then in general he is more sinful; Allaah Says (what means): {Have you seen he who has taken as his god his [own] desire, and Allaah has Sent him astray due to Knowledge and has set a seal upon his hearing and his heart and put over his vision a veil? So who will guide him after Allaah? Then will you not be reminded?}[Quran 45:23]
According to one of the two interpretations of the verse (it means): Allaah misguided him after the knowledge has reached him and after the evidence is established against him. However, it is not unlikely that the one who disobeys Allaah out of ignorance is equal in sin to the one who disobeyed Him knowingly. For instance, a person who is able to acquire knowledge while being able to do so but he did not endeavor to acquire it, then he is not excused for his ignorance as clarified by Ibn Al-Qayyim .
As regards your second question, it seems that you are referring to the verse in Chapter An-Noor in which Allaah Says (what means): {Bad statements are for bad people (or bad women for bad men) and bad people for bad statements (or bad men for bad women). Good statements are for good people (or good women for good men) and good people for good statements (or good men for good women)}[Quran 24:26]
The verse is different from the meaning which you mentioned in the question. For more benefit, please refer to Fatwa 88697.
Finally, we warn you against speaking on behalf of Allaah without knowledge as Allaah Says (what means): {And do not pursue that of which you have no knowledge. Indeed, the hearing, the sight and the heart about all those [one] will be questioned.}[Quran 17:36]
Allaah Knows best.