Timing is everything; the narrower the bandwidth of the communications channel, the more important context becomes if you want to avoid falling victim to Poe's law.

It's not obvious that intent is sarcastic when it expresses a commonly held position, unless the sarcastic person is well known to have different views - not so easy to discern on a site like HN. To be obvious to the casual reader, you need to articulate a position which goes to absurd extremes, eg

A bit alarming to see the government embracing an end-to-end chat system with perfect forward secrecy, considering that it impede economic growth in our identity-theft and espionage industries.

Of course, that might not be recognizable as sarcasm in some countries where such activities are of greater strategic importance.

To be fair, I think language barriers often make this much more difficult for folks.

Recognizing sarcasm generally requires context on the author. You can make assumptions that lead to this looking like sarcasm or you can take it on face value; both are fairly likely to have some users that would write the comment.

I think it's kind of silly to use for that reason.

Sarcasm in text never worked well though. You also have to remember that a large percentage of HN readership are not native English speakers.