Apologies for causing so many nerd panties to bind suddenly.
I remember Apple helping developers back in the day to get gaming performance acceptable in the mid-90s. I'm only suggesting that this be considered for the Facebook app.
Except most people aren't experiencing this issues. The Facebook app runs great on my year old iPhone 5 and my friend's iPhone 4S. I'm sure it's even better on the 5s.
My friends are flocking to the Galaxy Note 3. Partially due to the performance problems of their legacy iPhones, and partially due to the bigger screen. I think folks are having a problem watching their iPhone get hobbled intentionally by OS upgrades. To continue in the Apple phone line is to ensure this process will continue indefinitely. Android, which I've never been a fan of, continues to perform well years later.
So they're moving to a new Android phone because their old iPhone had performance problems? How does this even make any sense? Do they somehow think a new iPhone would perform the same as their old one? Not trying to imply that it's illogical to switch to Android, but that sure is a poor reason to do so.
And no, Apple does not intentionally "hobble" older devices. They actually support devices older than two years old unlike the vast majority of Android manufacturers. As hardware gets newer, software is written to take advantage of that new hardware. The iPhone 5s is twice as fast as the 5, which is twice as fast as the 4S, which is twice as fast as the 4. It's completely unreasonable to expect remotely similar performance from an iPhone 4 and an iPhone 5s. Did the iPhone 4 run iOS 4 far better than it runs iOS 7 now? You better believe it! Look at how much more demanding today's apps are compared to the apps of 2010. Look at how different iOS 7 is compared to iOS 4, both externally (visual translucency, for example) and internally (APIs and features).
Now, as to Android "performing well years later"- you must have a funny definition of "well", because older Android phones (many of which are stuck on Gingerbread) absolutely do not perform well. The state of Android is much better now than it was a few years ago, so this is a topic worth revisiting in 2015 or so. But phones released around the time of the iPhone 4 absolutely didn't stand the test of time.
I'm sorry the Facebook app is terrible for you and your friends, but you're really making a mountain out of a molehill.