When I was vegetarian, I remember being confused to why vegans didn't consume dairy and even accused them of "going too far"; but the truth is, I'd never looked into the commercial Dairy Industry and didn't have a clue about some of the things that happen. I thought that cows just produced milk and that was that...
Here are 3 facts I learned, that put me off dairy forever (in no order):

1) Interspecies Breastfeeding.
It sounds silly, but I'd never really thought about it in much detail, but cows milk, is breastmilk.
Cows are mammals, so produce milk to provide nutrition and immune protection to their babies.
Thinking about cows milk in its literal form of "breastmilk", really put me off dairy - and ultimately we're also mammals, so scientifically don't need to be consuming breastmilk past a year old (especially from another species!)

2) Female cows within the Dairy Industry are restrained and made pregnant.
As a woman, this really triggered me and I had no idea about this whilst consuming dairy...
In the commercial Dairy Industry, consumer demand for milk is high, so lots of breastmilk is needed. Cows now produce more milk than they naturally should...
As I mentioned above, female cows must be pregnant to produce milk, so to ensure the stock (their breastmilk), female cows are "suitably restrained" and put into "rape racks" so they cannot move. Sometimes their feet are also shackled.
A bull will then forcibly mate with her, or more often than not, a human will insert their arm into her rectum and insert a rod-like device called an A.l gun into her vagina, then cervix where bull semen is injected into her uterus, with the aim of making her pregnant.
3) Calves are taken away from their mothers.
Cows carry for 9 months, a similar timeframe to humans and in that time I do not doubt that they bond with their babies, just like we do.
In the Dairy Industry, calves are taken away from their mothers often within 24hrs of birth. There are videos you can find online of female cows running after trailers with their babies in and it's the most upsetting thing to watch. I know from experience that they also cry for their young. Like any mother would.
They are separated so humans can have the breastmilk. The farming world will claim that calves are separated from their mothers for their own safety, but also make the acknowledgement that they make more profit when they're separated. Milk = money.

It's never been easier to ditch dairy and the alternatives that are now available, are so good, that you don't have to compromise on taste or enjoying things like chocolate or cheese.
I hope that the above information makes you think about ditching dairy and encourages you to look into things in more detail.