There is growing concern about the harmful impact of pesticides on human health, agriculture and biodiversity, prompting calls from researchers to reduce their prevalence.
I think this is where we disagree, I don’t believe that clarifying someone’s expertise is an attack on their character. I don’t accept medical advice from people who have no expertise in medicine. It’s not a judgment on their character, is a matter of relevant expertise.
You seem to be a little too focused on the word "attack".
She made specific points and your response to those points was to fault to her expertise. You didn't respond to her points; you responded to her character.
She noted issues with the accuracy and relevance of the data used by the government in its assessment process.
She made this specific point. Her expertise is relevant to her statement as no evidence is offered. I'm making no judgement on her character by pointing out her expertise.
If a cop pulls you over for speeding and asks for your drivers license, it's not an ad hominem attack. Context is important and there is nuance to labeling arguments as ad hominem.
If Mary Lou McDonald was a toxicology expert her statement about the accuracy of the data would have more relevance.
If Mary Lou McDonald had outlined the actual issues with the accuracy of the data her statement would have more relevance.
She is not offering details about issues with the data, so her expertise is important context.
The argument that expertise is part of character, therefore any mention of expertise is a fallacious ad hominem argument ignores the importance of expertise in giving context to a statement. A statement about health obviously has more relevance coming from a doctor than an influencer (assuming they're not also a doctor).
That's the foundation of ad hominem. It doesn't matter whether a two year who knows nothing or an expert with a life of experience says "climate change is happening", because the expertise of the person making the statement has no bearing on the truth of the statement itself. The two year old who can barely think is still right, even though he's not an expert, and if you want to debate it then you have to debate whether climate change is happening, not whether the two year old knows anything.
Would you concede that in cases where no evidence is provided, a climate expert saying "climate change will affect x" has more validity than a non climate expert saying "climate change will not affect x"?
I'm not talking about the validity of an argument as no argument is made in either statement. So maybe validity was a poor choice of wording. Which statement would you trust more?