There is a rip on your scarf, you should knit it. bu doğru görünüyor mu?

I think the wording is natural enough. Just be aware, culturally, sometimes we can be quite agreeable as English speakers and less likely to directly give correction/directions to each other.
Even when it's intended to be helpful. If it were me I might point out the rip. And see what they say. It might be that they don't knit, like maybe it was a gift. Or they may have been busy. Then if you're quite a good knitter and you wanted to offer, you could.
But every group is different and you know the context. It might be totally fine 😊