No, the reaction is about 95% in his favour.
Why though? Are people of the opinion they should be allowed to sit in first class? Do they think it's unfair to have a higher class that excludes them? Do they feel that way on a plane too? Do they go to football or a theatre and demand to sit in a hospitality box?
If the complaint was to be taken seriously, it would likely be that first class would be enforced at both ends of the 700 to be consistent with other rolling stock and remove any chance of confusion (except there is no confusion; anyone who didn't know about declassification wouldn't be there in the first place).
Or is it that someone who HAS paid for first class might feel aggrieved that they opted to sit in the declassified portion which was full of people who hadn't paid the extra? If they got a seat, is it a problem? Should they get a refund as they didn't sit in an actual first class coach? Again, the solution is to not declassify it - so now the 'hack' won't work for anyone and thank you very much Mr Want-to-get-famous-for-15-minutes guy.
The DfT isn't going to fund removing those seats and replacing with regular standard class seats, and as has been stated above, the DfT must feel there's a market for first class on some of these routes. On others, first class is declassified just as happens daily on loads of services throughout the country and did on FCC and WAGN before GTR on the ECML.
Why no fuss about all the trains you can look up on OpenTrainTimes or RealTimeTrains and see as having no first class?
The dumbest thing is that this guy KNEW the score, yet seems to have gone out of his way to do something that resulted in this outcome - so must have done it to get famous and go viral, and I really can't believe 95% of people are supporting him. Even if they are in some way to 'stick it to the railway' I am convinced none of them are sitting themselves at the front of a 700 waiting for a revenue check.