It is very rare that content comes with malware, you can trust all uploads but should have an antivirus on just in case. If you're referring to Chrome's warnings, it has been returning them for clean files lately. You can force the download to go through by pressing Ctrl + J and then selecting to keep the file (you can scan the file on virustotal.com to be sure its clean if you don't have an antivirus). If you do find an infected file, please report it to the moderators, however we can definitively say that they are very rare (so far in 2019 we've only had one). If you want to disable Chrome's safe browsing, go to Settings, scroll down to Advanced, and you will see Safe Browsing there. If you're looking for a good free antivirus, we recommend
AVG or
Avast.