The reason that InBev are seen as a good thing in Ireland is that variety in Irish pubs died out decades ago, due to the actions of Guinness. InBev brining their portfolio to the market certainly shakes things up and I for one am glad when I see Leffe, Hoegaarden, etc. in a pub, because it means that I won't be stuck with a nitro tap stout.
In other countries, however, InBev look a lot less friendly. They tend to buy up a brewery which has a good share of a market they want into, change production methods, dumb down the beer to broaden it's appeal and use their marketing muscle to kill off the other small breweries competing in the same market. Globally they are a nasty predatory multinational, but in Ireland, there are only other predators for them to attack.
Another thing to consider is that, while InBev are certainly in the forefront when it comes to getting alternative beers into the local offie or pub, they can only do so because the demand is there. If they were not filling the niche, perhaps someone else would. I have often said that it is rather unfortunate that, even though Irish beer tastes are changing and more flavourful beers are being bought, the vast majority of them are imports, not Irish micro-brews.