By owning XRP you dont own a share in company that is ripple.You need to understand the difference and read as much as possible and available information of coin you are investing.

You are having it backwards. If they use value to improve the block-chain, it is a good thing for someone holding and potentially using the blockchain.
They hold a lot of XRP. "if their coin value goes down their value as a whole should go down" is simply false.

If XRP goes down, so does their wealth.
If XRP breaks, there is not much left for them. What value does a company with a broken tech have ?