Having a trademark doesn't forbid your competitors from talking about you.
1. User types CompanyFoo (whose real URL is www.companyfoo.com) into their address bar, which lands them on Google (because Google owns Chrome and pays billions for the privilege on other browsers).
2. Since Google will sell this keywords to others, many businesses always bid on their own brand name to ensure it comes up first.
3. Thus, an ad for CompanyFoo shows up first, even though www.companyfoo.com is the first search result, so when user clicks on the CompanyFoo ad Google takes its cut. Again, this is also because Google has done as much as possible to make ads as visually similar to SEO results as possible - just the teeny 'ad' banner, compare to the big yellow box of early Google.
I don't have as much objection for other companies buying branded keywords, but the way Google has set up things up they are taking their cut from everyone even when they are giving very little value.
There was a search engine that got really popular doing that. I think they were called Google..?
Either Google should take a note from the old days when they were not rent-seeking jerks but did no evil and actually distinguished search results and ads by placing the ads to the side bar.
Or their practical search monopoly and all the profitablity from there should be regulated to oblivion.
That's just what I think should happen. The sensible me understands that obviously neither is going to happen.
But from what I've seen, the vast majority of ads that incorporate a competitors trademark are not doing that, and making it very clear they are advertising an alternative to the trademark being referenced.
Google makes money with these so they allow it as long as the ad text does contain the trademark.