No, they aren't. I'm fairly new to FTB, but I run a small private server with a group of friends. Despite one of them (who got me to even look at FTB) protesting against GregTech (because he didn't care for the Macerator recipe, among other things) we went ahead with default GT anyway.
Personally, I loved it. The multi-block structures, the Chemical Reactor, all of it. But then this happened. And I started doing digging, and I'm aghast at not only Greg's attitude (again, someone I didn't even know about until recent history) but the attitude of people like yourself. You may not see crashing the client as malicious, but yours is not a statement of fact. mDiyo may be in the wrong as well, but Greg added client crashing code. Not mDyio - and I reiterate, I don't even know much about him, nor do I have any inherent desire to side with him. I will, however, actively side against anyone that feels the need to insert code which will crash a client for arbitrary reasons, and then attempt to foist that responsibility off on someone else.