I do not know what kind of comment you wrote, so I in the interest of curiosity I'll ask: Could it be that instead of stating in the comment both the relevant,

I do not know what kind of comment you wrote, so I in the interest of curiosity I'll ask: Could it be that instead of stating in the comment both the relevant, precise figures and a conclusion derived from them, you merely linked out to the PDF in a way that only by reading the PDF could your point be fully seen? By and large, on forums and social media it is heavily frowned upon to rely on outlinks and open ended reasoning. As in the line of thought: "if you will not state your point clearly for everyone to see at a glance and then back it up with sources, why should I bother?". It may seem unreasonable or even anti-intellectual at first until you draw parallels with in-person discussion: imagine someone describing their point in detail for 10 minutes only for the other person to hand over a whole book and say "you're ignorant, go read this and learn why you're so wrong". I will repeat again: I do not know what you actually said in that comment, but I've seen this play out a few times and my gut tells me that unless the point was extremely controversial, a deluge of downvotes is likely explained by this scenario.