"the" vs "those" as determiners

I'm editing a draft of a formal speech written by a non-native English speaker in which "those" is repeatedly used as a demonstrative adjective/determiner. My instinct is to change these instances of "those" to "the", but I'm having trouble explaining why in clear terms.

Technically, I don't think their usage is incorrect, but it feels unnatural to me. Am I wrong, and this is completely acceptable? Does the fact that the nouns paired with these determiners are followed by subordinate clauses indicate some sort of implied contrast, which makes it okay? Are there set rules for when to use "the" vs "those"?

Below are a couple examples from the text.

I'd like to thank those outstanding members, officials, and contributors who went above and beyond to make this dream a reality.

and

We should concentrate on those departments with the most serious issues.

I think either is fine, but there is a subtle difference.

Using "those" might imply that there are other outstanding members, officials and contributors who did not go above and beyond to make the dream a reality. You're only thanking the ones who did.

Changing it to "the" equates the two and doesn't really allow for this distinction.