You’d think so, but this is the second time OP has done it!
I use PayPal for this sort of thing. If the person you are paying insists on a ‘gift’ so they don’t have to pay fees then just pay them normally and add the extra couple of quid yourself, which is 100% worth it for the protection it gives.
As for this forum being mean, far from it! You can barely say anything on here without getting flagged.
Yes
So it’s advantageous for the banks and not the customer.
Learning from that experience on this occasion, I gathered an overwhelming amount of information about the fraudster before the transaction, I have his genuine address, his work, even his mum’s Facebook and I’ve verified all of it (and told the authorities) so I did as much as I could to find out who am I sending the money to, and all of it checks out. I know exactly who and where he is but can’t get him to return my money. I also made sure it was a deposit and not the full amount.
This is the first time I have ever used a forum and it just fascinates me how I’ve asked two questions in my opening post and yet it’s mostly been ignored, instead people are replying with more questions trying to me make feel bad, as I said, I’ve been conned, what do people get out of trying to make me feel worse?
Calling me will fully negligent is really helpful, thank you.
This thread should be closed now, the few comments and links provided so far that have been helpful are the best i will probably get.
Hi Peter
By the looks your questions were (a) can you do anything to get your money back and (b) does Monzo have the same powers as other banks. That’s all I can see that looks like questions. Both look to have been answered, albeit indirectly. The answers were essentially (a) report to Police and action fraud, and (b) yes, it’s a regular bank.
Anyone being defrauded a second time in the exact same way will expect a certain level of comeback, because the impression is that you have not learned anything. It’s only now that we can see you performed a good degree of due diligence by gathering so much information. Unfortunately Facebook Marketplace is like the wild west, and as you’ve seen, you can still end up stuck on the bad end of fraud. I’d definitely avoid like the plague and either buy direct from shops or use something like eBay (and PayPal) in future. I’m sorry that doesn’t help you but if nothing else you’ve learned a valuable lesson (i.e. don’t trust anyone!!)
Good luck in your future purchases.
Welcome to the monzo forum! 
I’d go round and shake the little scroat down if I were you.
I’d send his mother a message on Facebook
Yeah, actually, that first
Or send him a penny with reference “I know where u live”
Correct, we have a legal obligation to detect and prevent financial crime, restricting cash deposits is one of many controls that help banks achieve that.
Financial crime sounds like a abstract concept that doesn’t impact normal people. But it forms the backbone of how most other crimes are committed. Moving money gained by selling stolen goods is financial crime, also scam you suffered is another form of financial crime. Another well know example is convincing people to send their savings into “Safe Accounts”, many don’t think they’ll ever fall for something like that. But I’ve many examples of extremely complex and sophisticated scams that would fool all but the most experienced financial crime expert.
Preventing financial crime is big part of making sure many forms of criminal activity is unprofitable.
So yes preventing cash deposits is “advantageous for the banks and not the customer”. But preventing financial crime doesn’t make or save banks money, it a requirement of regulation that exists entirely for the public good.
“All crime is financial crime”
But you didn’t learn did you? You sent cash to someone in the least secure way. AGAIN!
How do you know all of that info is genuine?
I can tell you where I work, my address and anything else, none of it has to be true, especially if the pictures and name on Facebook aren’t actually me.
I think the OP recognises he’s been pretty naïve. You can stop kicking him now. 
Your wish is my command. 