For us the answer was "yes" as the crying was only about 2 minutes.
For my son at 7 months, we followed the Ferber method, as described in his book Solve Your Child's Sleep Problems: New, Revised, and Expanded Edition. Crying is a tiny part of the program, and this book should be read from cover to cover.
The first step was to establish a consistent sleeping schedule by waking our son up at the same time (we chose 7 am) everyday. This meant that in the evening (8:30? I forget now) he was really tired. This took about 3 weeks, and involved adjusting nap times and feeding schedule.(Note 1)
After the sleep schedule was consistent, we decreased the amount of food we fed him at night. Tapering and stopping the 11 pm feeding was pretty easy; he just ate more at 8 pm. The 2-3 am feeding was much harder. Bringing it from 6 oz to 1 oz was easy - took about a week - but getting him to stop that last ounce took another week.(Note 2) Finally, he ate more during the daytime, and was able to get through the whole night without getting hungry.(Note 3) He would still awaken a few times, and we had to rock him back to sleep, but he was mostly there.
So here we were, after a 4-6 week battle, with a kid who slept most of the night and had a consistent sleep schedule. We wanted to stop rocking him to sleep in the middle of the night. We wanted both us and him to sleep the whole night, but we very much dreaded the "Cry it out" phase.
It was anti-climatic. We kept him awake about 20 minutes past the time he normally fell asleep. We put him in his crib, no rocking. He cried and cried for about 2 minutes, then fell asleep. For middle of the night crying, we instead of jumping to run into his room, we walked slowly (60 seconds?) into his room and rocked him back to sleep. After a few days, he realized it he knew how to put himself to sleep without the rocking, and that the rocking was irritating - he preferred to sleep on his own.
He ever since has been a champion sleeper.
So in summary, "let baby cry at bedtime" is 100% ok as long as you take care of the preliminary stages first. I think just one day deciding that baby should go to bed at 9 pm, and never wake up is cruel.
Note 1: Not possible during active teething
Note 2: Our son at this point mostly on formula, but Ferber says how to do it with Breast feeding too.
Note 3: This is not possible with smaller babies, need to wait until they are a bit larger and chubbier. Not possible for a 4 month old; they are too hungry.