I think there was a small minority who were genuinely spiteful about the 20% rise. Most of the posts I saw were from people who were ideologically opposed to private education and felt that the VAT exemption was unfair. There was also the feeling that the vast, vast majority of families using private education wouldn't have to pull their children out - which largely seems to be the case.
As I said earlier, I'm a bit of an outlier. I'm not in a position to be able to afford private education, attended state school myself, and I'm firmly left-wing. However, I think given the absolute train wreck of our current state education, making it harder to access private education is the last thing we need right now. The money from the VAT won't even touch the sides trying to shore up the current shit-show that is going on in state schools right now (I was a school governor for 5+ years). I was/am very opposed to the VAT rise.
Nevertheless, I still don't think the two viewpoints are equal. Private education remains quite controversial, and it's an ideological position that many people are opposed to because it gives some children an advantage, many of whom who are already privileged. Laughing at vulnerable people not being able to afford to eat is not an ideological position, it's just punching down on the less fortunate.
And yes, I do think people expected Labour to be more sympathetic to vulnerable groups. They've always been the party to protect those in poverty, the disabled etc. But there are very real concerns that they're Tory-Lite at the moment - the courts have already said that changing disability benefits just to raise money is not acceptable, and will leave people in unacceptable poverty with no improved chances of being able to work. People are worried about what Labour are going to do to disability benefits because at the moment they're a lifeline for those who can't do all the things that other people take for granted. We're waiting for an announcement but it's pretty scary.
(I work FT as self-employed, but I also care for three disabled people and in addition, two years ago my DP collapsed with a neurological issue. He had a high-flying IT career and has been told they can't cure him and he will never work again. Not everyone on disability benefits are chancers - it's really, really shit having no choice but to rely on government handouts).