A lot of dogs seem to be really reactive.
I agree @lieselotte - I've had dogs all of my life - never less than three, and at one time had eight in the house (my 6 terriers and DDs great dane and staffie), but it is only the last 2 or 3 years that I have noticed the degree of aggression and reactivity that we are seeing now.
I think lockdown has had a lot to do with it - people have bought dogs because they were at home all day, and neither trained nor socialised them. In addition, once those people went back to work, the dogs have largely been left to be bored and lonely, after being used to a house full of people.
The other contributing factor is people buying dogs because they like the look of them, or because they want something "unusual", without taking into account the temperament and needs of the breed. This means that very active dogs are often condemned to a sedentary life - which frustrates them and makes them over-excitable, or people buy dogs they physically can't handle (and I swear I've met several people who are actually frightened of their own dog). Frequently these dogs are, at best, half trained. There are many working breeds which just aren't suitable as pets - they are too independent-minded. require far too much exercise and mental stimulation, and are often "one-man" dogs and will only really take notice of one person in the family.
It isn't the dogs' fault - but that doesn't stop the dogs being a problem.