Avram:
In a few of your comments, you have labeled me something that I am not. Whether this fits the technicality of מכנה שם לחבירו or not is not the issue. But I should clarify, so that you are not walking around believing that I am okay with kids being mechalel Shabbos just because telling them not to would be rejection.
For starters, we are dealing with a kid that is already acting out, not initial chinuch. The OTD kid is doing so in pain, though we may not know what precipitated it. This is not about the blame game either. What we do tell a kid is what will produce the best result for the kid. If imposing will on him just makes him rebel, then we need to find another option. No, I do not absolve the kid of responsibility either. But his acting out from his personal pain does not designate him as an apikores either.
The argument I make is that boundary setting, a critical part of basic chinuch, must be done right and at the proper time. At the wrong time, it does not convey a message of direction but a set of criteria to earn punishment. That message rejects, and has no place in chinuch. No one would be pleased to be ordered around like that, and at the very least, מה דעלך סני לחברך לא תעביד. If one needs to give this direction to a kid that is already OTD, or even struggling, there needs to be guidance how to accomplish that. I will share a general rule in all of chinuch. Absolutely everything that is done in the way of chinuch must be focused on bringing about the desired result of the child’s learning (whether information or behavior). The role of the mechanech (rebbe, teacher, or parent) is to teach, not control. There are times when it becomes necessary to engage in control, but that is not true chinuch, and should also be the exception. When we fail to teach אהבת השם to our children and talmidim, we have failed at our mission. No one is perfect, and many of us will have experienced failures.
I do not believe that boundaries are forms of rejection. But the kid needs to hear it as a boundary, not a criterion for punishment or tolerance. Hashem’s love for Klal Yisroel was ever present even after the חטא העגל. That needs to be our role model for how to love. Under the very worst conditions, Hashem never interrupted the מן or the בארה של מרים. He never rejected us, even throughout the turbulent years of the דור המדבר with a series of negative events. I humbly believe that HKB”H knows a lot better than humans, and that the love for a Yid needs to be unconditional. Ultimate rejection is not in our domain. If we are machmir on everything else in life, why not apply that to the cherishing of a Yiddishe neshomoh?