I agree, it's convenient to use such an option so you don't have to go to the site every time. I've never used this program, so I thought I'd give it a try. I downloaded the portable version of the program from the official site, checked for viruses with VirusTotal and to my surprise VirusTotal showed that the archive contains
Trojan.Malware.300983.susgen VirusTotal error?
P.S. I apologize for the off-topic.
I have been using ShareX for years, never had any issues nor got hacked, so I’ll also go with the false positive probability. Even my own software already got more hits than a single AV I never heard about.
Remember that most AVs only do pattern checking. If a malware fetches a server to steal your data, bytes for that feature can be labeled as such, and a legit software that also fetches a server - but to upload images - can mistakenly be detected as something potentially suspicious.