Oh yeah Twitter is cooked. Their Crashlytics SDK is awesome. Answers is good too. I actually think if they spun out their SDK biz, it would actually be a real interesting business.
IoT security is still so nascent that most vendors in it arent really spending much time architecting a secure layer. Frankly they don't really care if their products get co-opted for a DDOS attack. There's no harm to their customer. This will be a huge problem as time goes on.
These are all fairly standard VC behaviors frankly. If you didn't do enough diligence on him/her before, then it's your fault. Sorry to be blunt. The best advice I have heard is "VCs are like your Colombian drug suppliers in Scarface. Act accordingly". I have heard worst behaviors where it's more along the side of self-dealing, where if other investors wanted to sue, they have ground to.
This is why if people are wrong to celebrate raising VC money. Celebrate when you actually bootstrap the startup.