[rrobukef]

Because each university has university-wide rules forbidding sharing assignment solutions. It is explicitly forbidden even before starting the course unless the syllabus or professor directs you so. You can't "help" others on their own assignments by giving your solution. You can't receive direct "help" either.

Edit: here's the text of my alma mater: Any behavior of individual students by which they make it impossible or attempt to make it impossible to make a correct judgment about the knowledge, insight and/or skills of themselves or of other students, in whole or in part, is considered an irregularity that may give rise to an adjusted sanction.

A special form of such irregularity is plagiarism, i.e. the copying without adequate source reference of the work (ideas, texts, structures, designs, images, plans, codes, ...) of others or of previous work of one's own, in an identical manner. or in slightly modified form.

[https://www.kuleuven.be/onderwijs/oer/2021/?faculteit=500004... translated with Google]