It is very common in socialist circles to dismiss everything short of revolution (and just the right kind of revolution at that) as "reformism", "improving the servitude of wage slaves", "helping the ruling class stay in power", and so on. Most socialists aver that it's either revolution or nothing.
There is a large advantage in the all or nothing approach: Since actual revolution is extraordinarily difficult to impossible (in the industrialized western countries), one can safely call for revolution without having to actually do anything except repeat stale (even if 'correct') rhetoric. Everybody knows it isn't going to happen in the near future.
So too activists like you who want a revolution in diet: They can safely take the all-or-nothing approach because "reform" or incremental change, or slow change (which still takes a lot of work to achieve) leaves one, some, or many animals still being used for meat production, which is totally morally unacceptable in your thinking. Reducing animal suffering by 3% a year just isn't worth doing.
Changing diet is essentially a public health project. What I suggested above (making vegetarian food available and convenient) is an "environmental intervention". Environmental interventions are a standard approach, that works better than all or nothing arguments.
For example, in the AIDS epidemic, messaging evolved from avoidance, to safe sex, to harm reduction to effective chemical prevention. "Harm reduction" acknowledges that some people (quite a few, actually) will have anonymous or promiscuous sex, will have unprotected sex, will use recreational drugs, and so on. So, what can be done within the framework of what people actually do? Well, we first made condoms ubiquitous. We gave them away by the millions. The product (the condom) is a message: sex can be safer. We distributed clean needles and bleach kits to drug users, then we started to exchange new needles for old needles. More recently we started advising people to take a daily low dose of Truvada, a combination of two dissimilar anti-HIV medications, which practically eliminates the risk of transmission or new infection when taken daily without interruption.
These messages and interventions evolved over a 25 year period, and have made a significant difference. While they have significantly reduced, they have not eliminated HIV transmission. Elimination of HIV transmission will require an effective vaccine, something we have not, so far, been able to develop.
I submit that most of the people who are not already vegetarians will ignore your guilt trip rhetoric. If you want to change people's behavior (and not just convince them that you are right and they are wrong) you will have to come up with a strategy that makes a vegetarian diet convenient, attractive, and even "trendy".
So shut up with the guilt tripping and come up with something that will actually WORK.