I think your perspective is that of a business owner who regularly deals with a lot of people/customers/potential customers without any anonymity. Here, most people are anonymous, and only those who have bought/sold something from/to them might have their full names, addresses, numbers, etc. And that's the way it should be. I don't want my name published here, by a moderator or whoever, and uploading docs, even with info redacted, to an unencrypted file dump is an absolute no go. Besides that, even if I trust the staff completely, a staff account compromise would compromise all of those documents.
There are exceptions to this anonymity - when scams happen and mods publish the scammers details for others to check with. But the "this guy is not sharing info, he has something to hide" outlook is not appropriate. Just because someone is unwilling to share doesn't mean they are a scammer, and just because someone shares everything doesn't mean they are legitimate. All of the extra steps you listed don't increase the confidence of knowing for sure one way or the other.
Video calls, doc uploads, etc., I'd rather just take my chances on olx or sell for a bit lower to bulk purchasers.
And to take it to the next level, a video call should add another layer of security.
What's the point of redacting in the uploads if you're just going to do a VC and ask the seller to show the document?
Aadhar + pan + bank pass book
Do you actually have a passbook in 2022? I sure as hell don't, and I'm pretty sure 99% of people here wouldn't.
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Something else that just occurred to me, where is this forum hosted? Will upload of PII run afoul of IT laws regarding restriction of location of data storage/processing for Indian citizens?