Actually it is not ViaBTC impeding me to withdraw, but Electrum. When I enter the amount, it tells me that it is too small.
Are you creating a request in electrum receive tab?
If so, take note that you don't have to make any request in electrum to receive bitcoin. You can use any of addresses listed in "addresses" tab to receive bitcoin.
I guess the problem is that the base unit has been set to mBTC and with entering 0.00052172, you make a request to receive 0.00052172 mBTC which is equal to 0.00000052 BTC.
Again, you don't need to make any request.