As long as you are grounded in your Catholic faith, I wouldn’t see where it would really matter. As long as you can distinguish the heresy. However, I’m not sure what the Church’s official teaching is on this.
I do know that even the few scriptural passages she defines for the faithful, she allows for lattitude of interpretation, as long as the interpretation doesn’t
oppose the Catholic interpretation.
Example:
Matt 16. The foundation of the Church. The common Protestant argument is that the “rock” upon which Christ builds His Church is not the person of Peter, but rather Peter’s
confession. The Catholic interpretation (which is binding on the faithful) is of course that the “rock” is the person of Peter himself. However, in reality, both can be true. For it is because of Peter’s confession that the Father chose him (revealed who Jesus was through the Holy Spirit), and therefore Jesus chose him to be that “rock”. If you interpret it that way you are not accepting an interpretation
contrary to Catholic teaching.
Since many Protestant sermons are based upon Protestant interpretations, I would question why one would want to listen to Protestant sermons in the first place when we have some of the best sermons here in the Catholic Church, and you know that you have much better odds of avoiding heresy.
However, having said that…and in a spirit of charity…having come from a Protestant background myself…I would agree with you that there are some wonderful sermons that Protestant pastors provide to their flocks.
Btw, just because someone is a gifted speaker and/or has a charismatic personality, does not necessarily mean that their sermons are free of heresy, or even good.
Many ex-Catholics have strayed and left the Catholic Church based on that, and because they are often ignorant of the teachings of their own faith. So, in summary I would say although there are some wonderful insights that some Protestants have to offer, unless you are grounded you are walking on shaky ground that could turn into an earthquake and uproot a large tree that could fall on your house or do worse damage and…okay, sorry, I digress…