This word is used to describe people who attempt to claim the moral high ground, usually with the purpose of looking good in other peoples eyes, with or without actual sincerity is irrelevant as the purpose of acting so is for egotistical/social purposes.
Often used by internet and IRL white knights or attention whores to gain popularity/ego stroking, used when an opportunity presents itself to put someone down.
Saccharite comments are usually emotionally exploitative and entirely unnecessary to the intent of discussion.
Saccharite comments in the writers experience, tend to be the result of a lack of knowledge of the context or information, a derogatory expression of mount stupid.
The word is derived from saccharin, a type of artificial sweetener that's bad for you in large quantities.
"looks like he'll never get ahead in life"
"oh, that's so sick, don't you know about how many grieving mothers and...(rant) you should feel ashamed!"
(more people going into the shame game/sucking commenters dick)
"it's a movie prop I've been working on, stop being a saccharite."