Opening multiple accounts to try to get as many bonuses as possible is against the rules in any casino in the world, and I think it's unfair to put the blame on us
In this scenario, OP was not trying to get as many bonuses as possible, were they?
In this scenario, their deposit had no bonus terms associated thereof and they were betting like any other regular player.
In this scenario, whether this was their first or hundredth account, the advantage given to them with their bets is the same: zero.
In this scenario,
you are in the wrong. You are blatantly stealing.