Sometimes I will use the inclusive ‘we’ to make it more clear that I’m just trying to assist… especially in a public/collaborative setting.
“Could we use sshd? It might be simpler.”
“Has anyone tried using sshd? Maybe it will work?”
Another approach (popular among counsellors and management types) is to Ask to Ask, e.g. “Do you mind if I make a suggestion?”
It is cultural though, some people are bound to read offense into either approach. (Especially the second one, especially among people who think they’re beyond decency).
Why didn’t you just tell your colleague he’s a dolt for not accepting feedback and assuming you were out to get him?
“Could you explain the issue with using sshd here?”