Being 'truthful' is often cover for being offensive or misleading.
There is also the issue of whether someone means truth as in a verifiable fact or truth as in what they believe the truth to be. Or even truth as in 'To tell you the truth...' followed by their opinion.
In the second and third cases, saying something is 'truth' isn't cover for it being offensive.
In the first case, phrasing does matter, and if something is a verifiable fact, trying to phrase it inoffensively won't make it not true.