What's up with tagging murals here?

[Djentmaster001]

I understand it is part of the "culture" and it is common, but compared to cities I've lived in or travelled, murals in Montreal are defaced and vandalised much more often and it's pathetic honestly. I have a lot of friends in Miami who do works in Wynwood and other cities and don't want to step foot here because they know their art will get defaced quickly. Compared to Wynwood for example, tagging is less common there, much much less. Yesterday I walked in Le Plateau for the first time in a while and most of the newer murals and ones that are two years old are completely covered in tags. Is there some turf war going on? is it jealous graffiti artists who can't make it big? is it anti-gentrification activists who think murals and art = gentrification? all three? it just sucks cause everytime I want to show off art here to friends, or my other friend who has a blog, they can't take proper pics because it's vandalised and it is a disservice to the city and pathetic.