Seems you're saying it might be illegal to convert a HTML file to PDF format, or to use a screen reader to read the text.
I wonder in which country you are (where apparently there can be laws like that)
Say the education department has a requirement that where ever a student's grades are displayed, the legend to explain their meaning and a disclaimer about limitations is included. It could even be a hard requirement (like, they got sued once for not doing it so their lawyers have told them they must enforce this). So they are careful that in their app, that requirement is always satisfied, since failing to do that could lead to harmful confusion that could impact a student.
So in their view the "document" they made public is the fully rendered version of that. If you print it out you are effectively doing a transformation that preserves its form and essential characteristics. If you screen shot it, cut out the disclaimers and legend and then paste it on a public web site ... you could create the same problems that you are by taking raw data out of the API.
I know technologists like to think that way but very often the law doesn't work like that. They will think about intent - was the intent to give you the raw data or was the intent to convey a specific representation of it that may omit some parts or further transform or presentation layer changes to achieve a different final result to what the raw data would have conveyed?
If it is the latter then that is the "public document" you have access to, not the raw data from the API.