It's all a matter of choices, safe cosleeping is the best and safest choice for some, especially for babies who just won't sleep on their own no matter what...
My baby hadn't read any of the books I had and he refused to agree with the advice professionals had given me (& that I felt sounded very right).
From the moment he was born he had no intention of being anywhere but in my arms or on my chest. It was killing me - the exhaustion and anxiety. I had to cosleep, though was a struggle to even get him to sleep within safe cosleeping guidelines. I could never relax even when asleep as I was terrified he'd have a fatal accident. no pillows or duvet on the bed, no dh as he slept too heavily, erghhhh.
I bought a hammock off a kind mumsnetter and got him to sleep in that for 45m at a time. I remember how much I rejoiced about a whole 45 mins - God how depressing looking back, but at the time it was amazing!
And listening to everyone saying how their baby started to sleep through at 3, 4, 5 months... Mine didn't until over 3 years old.
So at about six months, I had to relax and cosleep as safely as possible, but with me actually letting myself deep sleep not fighting it all the time.
It wasnt what I'd have chosen, but it was that or go stir crazy. Looking back I have no idea how I got through it, but I guess I didn't have a choice. He had bad silent reflux and now I wouldn't have let professionals fob me off, but hindsight is 20:20.
Now at 3, ds still creeps into my bed but now I'm not worried by it - just bloody uncomfortable, star fish sharp toe nailed evil child sleeper grrrr :)