It is about actions
Criticise the actions, not the person. Not: “You make Bonnie feel uncomfortable when you stroke her arm while you speak to her”. Rather: “People differ regarding how touchy-feely they are. Many people feel uncomfortable when colleagues touch them for more than a second or so. They feel it is an invasion of their personal boundaries and they withdraw, or mentally or physically recoil. In a diverse company like ours, which relies on cooperation and teamwork, it is important to respect a colleague’s boundaries and how you make them feel.” This should be enough to change behaviour in a company where respect for others is a basic, unstated value.
I can hear your say “people must just grow up and accept criticism”. To some extent, this is true, but few people flourish on criticism. It needs resilience and a high level of emotional intelligence, of which a strong element is empathy. Most people do not have this in sufficient measure and your function, as a manager, or as a colleague, is to optimise productivity by leading/guiding them to their best behaviour.
Try to remember the worst criticism you have ever received. How did it make you physically feel? How did it affect your mood and your self-esteem? What was your primary emotion – hurt, embarrassment, motivation, anger, remorse, happiness, a high level of creativity?
Some people never get the message: https://www.youtube.com/watch?v=gdp4sPviV74. Vitalsmarts.com