As long as people upvote "I learnt something I agree with," and not "I learnt something I disagree with," the effect is the same, the amplification is just tuned a bit. Having a different standard for upvotes and downvotes doesn't do much. If you get less upvotes, it is effectively as if you got more downvotes.
I found it curious that something is never mentioned in that post. That is, not voting at all.
So yeah, I generally agree with PG in that
> it's ok to use the up and down arrows to express agreement
But he never said to do it in a trigger-happy manner. There can be many other reasons to vote, but when the reasoning is 'agreement/disagreement', voting IMHO should be done when you strongly agree or strongly disagree; this way you allow some "space" in between for freedom of expression.
So my current take on this whole vote up/down to convey agreement/dissagreement discussion would be not voting at all unless you find it pertinent.
Also IMHO, in other types of reasoning one should be a bit faster to downvote, for example 'rudeness', or worse, 'hate messages', for those ones I downvote immediately, or flag and sometimes even educate (if the person seems to be just confused, and I make one attempt only, if the person is not interested in changing their mind, I skip).
Other types of reasoning deserve a different approach, for example; Interesting comments I upvote even if I don't agree. Well redacted but uninteresting comments I leave untouched (I don't vote up nor down).
And there are many other considerations for different scenarios and different types of reasoning, I mostly prefer not to waste time, but I liked this post about kindness and find the topic of community very engaging and relevant to me. Maybe because I'm starting to build a community myself.
I admit that I'm a bit faster to upvote, for anything that deserves positive feedback; attention, approval, agreement, endorsement, celebration, applause, kudos, kindness, etc. And I'm OK with that.
As long as people upvote "I learnt something I agree with," and not "I learnt something I disagree with," the effect is the same, the amplification is just tuned a bit. Having a different standard for upvotes and downvotes doesn't do much. If you get less upvotes, it is effectively as if you got more downvotes.