Uncertainty is mentally taxing, because one has to build, maintain, and use more mental models compared to someone who is more certain. One would think that makes it a good tool for signaling intelligence (and I think that at least partly motivates me to be conspicuously uncertain, such as here), but fortunately or unfortunately (I'm not sure which ;) I don't see many other people doing this.
Vipul Naik was talking about uncertainty as virtue signaling, which is related to but distinct from my point about uncertainty as intelligence signaling. (For the former, it's perhaps sufficient to pepper "not sure" throughout your writing, like Vipul was complaining about, but for the latter you have to demonstrate familiarity with and usage of a variety of theories/models that you haven't yet ruled out.)
If you want to explore the community more, I recommend reading the Library, checking recent Curated posts, seeing if there are any meetups in your area, and checking out the Getting Started section of the LessWrong FAQ.
The Open Thread sequence is here.