No, they are not harming Bitcoin price.  XRP and Stellar have a different market, and possibly have different community.  XRP whales possibly wanted to ride the hype of BTC market and started pumping XRP to maximize the effect of the bullish Bitcoin.  So I think the surge in price of XRP is planned and Bitcoin has nothing to do about it and vice-versa. 

As of the Bitcoin price crash, people wanted to make a profit so it normal to see people sell their holdings when a reasonable profit is seen.  Aside from that, it is not the XRP people who made Bitcoin market crash but rather some huge group of leverage traders that liquidated their derivative holdings resulting in a huge price crash of BTC this past days.