1) if the jungler knows what hes doing mundo and shyv can be great for a team but they aren't picked for ganks, they are picked for counter-jungling and should not be picked if the lanes don't have the cc to make up for their lack of it or else they made a poor choice of champion. in which case feel free to blame them and even more if they are playing them like a jungler who can gank rather than counterjungling the other team to hell.
2)I personally will always try to help a camped lane but many laners do not understand the meaning of the word camped. when a lane is camped it is usually because it is a) being pushed hard, b) all of their other lanes are pushed and your lane happens to have the best advantage over your lane opponent or c) you are the easiest to gank and they want to snoball. In many of these cases the jungler is either preoccupied trying to help the other pushed lanes or is trying to control objectives or buffs. Another misconception is that two consecutive successful ganks means that a jungler is camping you. Many times a laner has said they were being camped as another lane is being ganked and i look stupid because I came to help them and left the rest of my team open to ganks. But yes one of the junglers jobs is to counter gank and if a lane is being camped he should be there. One personal experience had me laughing because our mid lane was being camped by their jungle and i was off to the back by the second turret and trying to make sure they couldnt dive our mid and she pinged me to back off like 15 times and when they dove she blamed me for baiting him into staying despite the fact that the jungler was there for a good 10 seconds before i got there to help.