There is growing concern about the harmful impact of pesticides on human health, agriculture and biodiversity, prompting calls from researchers to reduce their prevalence.
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?
Well if we're talking about trust, then we are talking about belief, and if you're moving into the realm of belief then there is no point in any further discussion of reason.
You initially claimed that mentioning expertise was an ad hominem fallacy. That's what we've been discussing. Can you now appreciate that mentioning expertise in this case is not an ad hominem fallacy?