Whenever you tell people that you let your baby cry themselves to sleep, even when it is not the norm, there still those that judge you. How could you do that? I'd never let any of mine do that. You should appreciate the fact that they're there. Etc. It's the same with time out/time in. Sometimes you can't do time in, sometimes you need time out but put that on a pro time in page and you're a horrible person. WTF is up with that? How can you not try to be like these people say you should be like?
Oh hun, I don't know who is saying that to you but they aren't there, at the moment in that time when you feel like you are going insane, going to scream, lash out - it's easy for people to make off handed comments like that when they are not there! You are exactly right when you say you can't always do time in - sometimes it won't be effective, sometimes you can't b/c you have another child to look after. That is like all aspects of parenting, you use the tools you know, have available at the time to get through the situation as best you can. Far out, if only parenting was as simple as those who say the above, but we know it isn't.