asking for help about "tense"
I decided that people under 18 should be excluded because most of them are students and looking for their first jobs, and also I decided at this stage just to focus on men who were in employment.

Why in this sentence using simple tense to “students” whereas using simple past tense to “men”. Maybe in this moment “students” are still studying at college and the “men” may lose their jobs? I’m confusing with that.

Question

asking for help about "tense"
I decided that people under 18 should be excluded because most of them are students and looking for their first jobs, and also I decided at this stage just to focus on men who were in employment.

Why in this sentence using simple tense to “students” whereas using simple past tense to “men”. Maybe in this moment “students” are still studying at college and the “men” may lose their jobs?  I’m confusing with that.

Answer

The action of "decided" happened in the past which is why it is past tense.  The students are currently 18 which is why they are in the present tense "are".  However, to be consistent, the verb for the men should also be in the present and in the form of "are employed".

Answer

The writer used "are" (present simple) for a general fact. That's all. :)