Most dog owners are respnsible but there are a few who aren't.
A great many of them aren't. This isn't personal opinion or an arbitrary, sweeping judgement: the evidence is directly proportionate to the piles of shit on public view everywhere.
I was walking up my lane (no pavements) only the other day to the sight of a dog owner stopping to let his dog take a shit on my driveway. I had to stop him and firmly request that he not allow dog to defecate on my drive. He didn't bother to apologise or even respond: it's as if he felt justifiably entitled to foul someone else's property without remonstration.
Our local beach has a 'no dogs' and dog friendly area. It's not enforced and there are always dogs on the 'no dogs' part. Along with the shit, in an area where children play.
It's not the fault of the dogs. Dogs are beautiful animals. It's the owners who are wholly at fault here, along with the assumption that they have an absolute right to let their beloved mutts make life messier and less comfortable for other people.
Most are responsible? That just isn't the case.