Yes the same rules apply to stock and agency photographs as apply to all other copyright works, when it comes to fair dealing. The difference is that, as you note, the agencies take a pro-active approach to protecting the works they manage on behalf of the photographers they represent.
Therefore you need to be very clear about what constitutes fair dealing under the criticism and review exception.
says that the criticism or review must be "of that or another work or of a performance of a work". In other words you cannot use a photograph of some activity or person in order to criticise the activity or person or their views. The criticisn must be of a copyright work - either the photograph itself, or a work which is the subject of the photograph. What's more, use of the photograph must be necessary in order to fully carry out the criticism etc. So for instance if you wished to make a critical appraisal of, say, a piece of sculpture recently placed on the fourth plinth in Trafalgar Square, using a photograph of it might well be entirely justified if the wider public was unaware of what the work looked like. It would be less justifiable to use a picture of, say, a work such as the Angel of the North, because there would be little need to refer to the photograph in order to criticise Anthony Gormley's work. Obviously each case will need to be judged on its merits, but the fair dealing exception can't just be used as an excuse not to pay for licence.
What's more, if your use could reasonably defined as reporting current events, then the use of photographs is specifically excluded. Arguably this is what was so egregious about the BBC's use
of a picture of scene from a Manchester street following New Year's Eve 2015, which they lifted from a social media site without permission and which went viral at the time. Only later did the Corporation try to dress this up as a critical review of the photograph itself, once they had been caught out.
The second thing to bear in mind is that if, as seems likely, you use the entire photograph, you will have used a substantial part of the work, which again may well count against the 'fair' in fair dealing. Contrast this situation with a piece of literary criticism, where a sentence or two may need to be quoted in order to illustrate the author's style or some other aspect of the work. That would be acceptable, and indeed it illustrates exactly the purpose of this fair dealing exception.
And of course any use must be accompanied by a credit for the photographer.
So carefully examine why you need to use a photograph, and only if you feel it is essential in order to convey some information which mere words can't do, then you are probably on safer ground. However don't be surprised if Getty's lawyers don't see things from your point of view!