Is there really any significant social pressure to make a new years resolution?
I more see it as an option to make decisions at the same time as others, which some might find useful for reasons I will describe later in this post.
You describe the service as an option to make those that succeed look good/get attention, and those that fail look bad (publicly).
You probably intended this as a complaint, but to me it seems like a more neutral thing, if words with more neutral connotations were used.
Some people might have trouble staying with their decisions if they just made the decision, at some random time.
Announcing their decision creates an additional incentive for them to succeed, which I reckon for some people is enough to push them past the edge into success.
Creating disincentives for oneself for things that seem appealing in the short term is a valid course of action to help one make preferred decisions.
People are not perfectly rational. Knowing this helps them plan things to avoid making poor decisions.
Having it at new years is nice for aesthetic reasons, and having a designated day for it makes people more comfortable announcing their decision, and also solves the problem of people putting things off. Some people will repeatedly decide "oh, I'll do it next month/week."
With new years, there's a definitive day, where its harder to delay it. (of course, one can say "oh, I'll do it next new years.", but that's kind of a ways away, which makes it less likely)
Generally, new years resolutions are an option, not anything people are socially forced into, from my experience.
Note that I am only a high school student, so I may be less aware of affects of social things, or other things one learns abouth through life experience.