I wouldnt say spamming alone is stealing money from the system. Nor would I say spam makes the value of steem go down.

It definitely wont help the value of steem rise, but you know what will? Voting on actual content. If your spending all of your voting power on flagging (a potentially infinite amount) of spammers then your fighting an unwinnable war, while good content passes by making nothing.

I would rather see good content get the rewards that they deserve, then see bad content get stripped of rewards they dont. The real issue here isnt that people are spamming, but that spam actually gets votes.