Indian here. You are correct. Expecting any employed Indian software developer to not be able to spare 1$ is stupid. Like how exactly poor do you think we are?!
I think the point was that if an aspirational minimum wage worker on a borrowed computer wants to put up a PR then it would cost them less than ten minutes of wages to afford $1USD in the US, while the same worker in India would need to put up about half a day's wages.
This is very noble in theory, but in practice you're not going to get many high-quality PRs from someone who's never been paid to write software and has no financial support.
It's not that outrageous. Apparently, 90% of India is living on less than $10 per day (https://ourworldindata.org/grapher/share-living-with-less-th...)