The attack on XRP is an attack to all. This is why some other altcoin as are dumping as well
No, that's not really an attack to all. This lawsuit is just specific for the Ripple. Don't think that because a lawsuit was filed to Ripple they're including in this battle bitcoin, ethereum and other big names in the market. That's not the reality of this. This is only a battle for XRP and if the market is going down because of it, remember that we are in a speculative market for which every news is affecting it.
because they knew, they could also be sued the same way as SEC did to Ripple.
As long as they haven't done anything malicious and suspicious that violates SEC's ruling, why they have to think of it?