Complete and utter nonsense.
Business and personal relationships can most certainly be separated, it just takes the right mindset and the willingness to set personal boundaries. However, if you are telling your employees "come in in shorts, drink beer, don't leave the office, we are all just friends here" you're intentionally putting up barriers to forming that mindset.... You don't have the same sort of relationship with your dad as you so with your spouse as you do with your best friend as you do with your good friends as you do with an acquaintance as you do with a stranger. This is normal.
Learning to work well with people who you don't particularly like is a skill. One that is learnable. Children have problems with it but adults should know better and if they don't know better they should be fired and replaced with people who can act like adults. "Working well with others" is something one is taught in kindergarten, it is mandatory for the workplace.
There's plenty of people I don't particularly like that I work with, that I know I wouldn't get along with on a personal level but I don't have issues working with them. People who I hold very, very different core values from me and people who have fringe political beliefs. But I don't have issues with them at work. I wouldn't want to socialize with them though.
Avoiding offending someone is easy, it's called avoiding saying offensive things or things "considered offensive," otherwise known as "being nice to others." Once again, we learned this in kindergarten.
If nobody is helping you with business problems unless you are friends or have "common ground" you have a very, very dysfunctional organization and it needs serious help. Even worse if everyone underminds each other. Not being friends with a coworker is not an excuseable reason for undermining them and at that point you are dealing with an office full of psychopaths and children. Forcing them to socialize with each other isn't going to fix the larger core issue.
What about customers? Do you need to 'get to know' your customers personally before you can work with them too? I'd imagine that would be a huge barrier to new customer acquisition. "Sorry, we can't give you a quote until we 'know your motivations(?)' and get to know your pets names. Meet at the pub at 5?"
The toxic workplaces you have described have nothing to do with a lack of coworker socialization.