Definitely agree 100%. Everybody gets to decide for themselves where their line is for what they will tolerate and what they will not. Especially for professionals. It is easy to say that someone else should toughen up and allow others to treat them in ways that are harmful to them.

There are many behaviors related to therapy that one could use the toughen up line for. We could tell people that self harm, especially in reactions to what happens in therapy, that they should just toughen up rather than self harm. When clients express fears in therapy, we should just tell them to toughen up. I have read once or twice that people are even afraid of their therapists coming closer to them or trying to touch them, they should just toughen up as well. We could probably dispense with many issues people bring up here by just telling people to toughen up.

Telling people to toughen up in response to what makes them fearful or upset is terrible advice in any situation. It's essential to being human that everyone gets to choose when to get out and when to stay in, when to be tough and when to be soft. Finding what works for you is the key.