Requesting a source is usually a low-effort escape. They don’t actually want to review your sources. They much prefer that you don’t provide a source, so that their comment appears to be the last word.

When you do provide sources, those sources seem to get disappeared very quickly. Almost as if the guy you were providing the source to reported it, instead of considering it.

Its generally faster to look up things yourself, than to wait for a reply from a stranger on the internet. Everyone online knows how to look things up, so requesting a source is just another way of admitting they don’t want to look it up themselves, and are hoping you wont even spoon feed them.