I am a dog owner. Yes, dogs need off lead time, but its my responsibility that they get that without annoying other people or using public areas like parks, which are often also the only safe places for kids to ride a bike or chase a ball etc.
I agree with all posters above saying that its not fair for a dog to be always on a lead, to not be allowed to wander free, to sniff, to approach other dogs etc. But it's up to me as an owner to find somewhere appropriate for that to happen, and I don't believe public parks are that place. If there nowhere near me for that to happen, then I need to source somewhere and find a solution. That's on me as a dog owner. And needs to be factored in before I get a dog.
There are places where dogs are allowed and permitted off lead, and it really annoys me to see dogs off lead in areas where there are signs and notices for dogs to be on them. Only to be met with "oh but they need to run free, oh buts it not fair for them to be tied up all the time." - all true, but its on you as a dog owner to sort that, even if it costs you more in time, money and inconvenience! And if you can't do that, you shouldn't have a dog.
I live right beside a massive park. It would certainly be easier for me to let my dog off there for exercise, but its clearly sign posted dogs to be on a lead. So my dog is on a lead in that park. I travel to a further walk area for off lead time, or pay to use open dog parks.
People who dislike dogs, or are afraid of dogs, should be able to go to places that have signs saying all dogs on leads and for that to be respected. If you want your dog off lead, go to places without those signs, even if it inconveniences you.
At the same time, if you want to avoid dogs, you can't expect dogs to be on lead everywhere you go - if you are somewhere without these restrictions, you can't dictate that there are no dogs off lead because that isn't fair either.