To vote i need to deposit BTC first? Counterparty shows a message that at least
BTC0.0005 is needed for the transaction.

I wonder how many votes gets lost because of this.
it is the great problem with the counterparty assets, the amount required is higher thant the default 10k satoshis, it is a real pity and in my opinion unnecesary, but too everyone can get 50k satoshis for it, if someone does not vote because that 50k, well in the worst case you can do some fauceting for get it