It called not only being polite and professional but the fact is you can't always just tell. Amd nit everyone who is trans has had or will have medical procedures.
And how the questions are asked is important.
They should be designed to encourage divulging
medically useful info. Blunt dwelling upon
reassignment is not only limiting the info provided,
it would likely discourage anyone not reassigned
from volunteering useful info.
It reminds me of the 988 Suicide Hotline. Much
research went into choosing the recorded voice
used, the on-hold music, & other aspects. The
resulting improvement was a small percentage.
But small as it was, it prevented tens of thousands
of people from hanging up because they were
discouraged. Many lives are at stake.
Things are more complex than many realize.
An open mind is better than leaping to vexation.