Sharing or uploading someone else's thesis without permission can violate copyright laws and academic integrity policies. It’s important to respect the original author’s rights and obtain permission before sharing their work, especially if it's for purposes other than private study or research

I agree. But under Creative Commons -or permission- Is it appropriate to upload them to ResearchGate?

All theses once approved and submitted to university or any Institution of research become joint property of University and Scholar .

The theses can be used for non commercial academic purposes. For republishing entire thesis you need permission form university or author. One can cite parts of thesis with due reference given

Supervisors input in thesis is recognised, and their name is published on the work similar to editors. Many supervisors publish theses or articles of their apprentices because they have interest or research points for publication. However, even if author is not on researchgate or other platform, the credit should be given to the author.