I think you misunderstand both systems, and personally I think Safecoin is less vulnerable to “hacking” as you call it than Bitcoin.
bitcoin uses proof of work, but this can be forged if you control 50% of the nodes on the network. The rewards system of bitcoin actually encourages separate miners to come together in pools, which actually makes this likely - in fact it has already happened several times that a mining pool has gained control of >50% and the system has relied on the pools a) not abusing this position to forge transactions, and b) voluntarily scaling their activity back by members migrating to other pools. Note: a 50% bitcoin attack gains you control of the entire blockchain allowing you to steal any amount from any address.
Safecoin uses proof or resource, and according the the maths cannot be forged until you control >75% (or more quite possibly) of the nodes, in order to control a small part of the Safecoin (not everything) - I’m not sure if the limitation is to coin held by a single node, but it is along those lines, and means the risk is to a small, possibly miniscule, part of the network (need detail on this!). Also, there is no “pooling” incentive to the degree that there is in bitcoin, making this much less likely. This is because everyone can earn, because the system uses proof of resource rather than proof of work.
So Safecoin is safer than bitcoin because: a) 75% (or more) versus 50% attack needed, b) much less incentive to “pool” nodes - I can’t see any at the moment but let’s see what happens, and c) A 75% attack only affects some of the issued Safecoin, I believe a tiny fraction (but need confirmation of that), whereas a 50% bitcoin attack gives the ability to forge transactions for any address on the blockchain (this is a massive difference).