Think about what you are saying when framed in the most cynical fashion. 'How is basing my opinion of an idea, not on what is said but instead on my opinion of the speaker, a sign of immaturity.' The claim to signal to noise is little more than a high brow ad hominem, rather than an actual rationale. And similarly your choice of adjective of "rational", is little more than begging the question.
Of course this is not taking your words in good faith, but it's also not straw manning you.
It is when the reason for deeming an idea foolish is the fact that a specific person said it. Most evident case of this is the lab leak theory, which became a complete taboo after Trump advocated it (though there obviously were other forces at play as well). https://www.vanityfair.com/news/2021/06/the-lab-leak-theory-...
Of course this is not taking your words in good faith, but it's also not straw manning you.