You should be a kind person.
The best outcome is when people overcome the dysphoria, not when we all pretend it's ok.
We observe much worse acute and long term outcomes, across a variety of dimensions, when transgender people are not permitted to transition.
Homophobes insist that they are telling "the truth" when they insist that all gay people are going to hell and that marriage should not be allowed for gay people. Racists insist that they are telling "the truth" when they insist that black people are simply more violent than white people and that black people should be treated differently by the justice system. Sexists insist that they are telling "the truth' when they insist that women are not capable of holding positions of leadership in business or politics and that their role is only to raise children.
I see no reason why transphobia would be different.
The harm of social transition is relatively minor and easily reversible. It's not as concerning, but it still perpetuates the phenomenon as 'tolerable'.
The harm of physical transition is permanent and devastating. We should consider the precautionary principle when engaging in irreversible actions.
Puberty blockers, sex hormones, mastectomies, and the rest are not compassionate treatments for dysphoric youths, but children are being fast-tracked into these decisions without much thought for how likely they'll be to regret it. Certainly many do, and it's an awful tragedy.
As all humans have before two seconds ago, we should let children grow into their bodies, and then they can make better-informed decisions as adults.
My main point being: this stuff is absolutely unacceptable for children, and adults are free to behave however they want, but I won't 'accept' it or go along with it.
I'm asking you to be kind. I hope you understand why people perceive you as unkind.
I'm totally willing to be kind and treat other people with respect. Never claimed otherwise.
But I also hope people see the errors of their ways, how harmful it can be, and to not try to indulge children and teenagers who get caught up in it. Leave the kids alone.
A large number of transgender people will find your viewpoint to be fundamentally disrespectful. It will not be possible for you to come across as respectful, no matter how much you insist on it. This is why I ask you to consider how the recipients of your words experience them as a better judge of whether you are behaving kindly.