Because it IS dangerous. Trek lore has established that mind melds carry the risk of neurological damage, emotional overload, and Panar Syndrome in the melder.
And even if all of those risks are mitigated, mind-melds are incredibly personal and Vulcans don't engage in them flippantly.
i haven't watched modern trek because blehhhh, but i presume it's just used as a deus ex machina?
"ah crap we don't have a sensible solution to this situation, let's just have them mind meld to get the information", shit like that?
that’s kinda different though… enterprise happened before the kir’shara discovery which changed vulcan society from “telepathy taboo” to “telepathy okay”. in their taboo society, there were references to the fact that pa’nar syndrome was incurable only because anyone with it were outcasts and thus undeserving of help
after the discovery of the kir’shara, vulcan society changed and their attitudes to mind melds in particular changed significantly
They always were. Even when Spock was using them, he only used them when there was no other choice, and even then, there was no generally no small risk to both parties.
From Enterprise, mind melds are treated as something both sensitive and private. Things you do with someone you trust. That seems to have carried over in the intervening centuries, but you're still not meant to meld with everything willy-nilly.
No. I was being snide and should have been more clear:
Janeway, I believe, was an especially unscrupulous captain who too often crossed the line to get what she wanted. This often included getting Tuvok, one way or another, to perform mind-melds under morally dubious circumstances. Sometimes Tuvok would undertake such endeavors on his own, without any prompting from Janeway, even without her knowledge at times.