They aren’t taxing love they’re taxing money.

We always tax money when it transfers from one person or entity to another.

No we don’t. In fact we rarely tax intra-family money transfers. When I pay for my kids’ college, that’s not taxed. Buy then a car at 16 - untaxed.

Right and give them the car two years later and it is taxed, subject to the gift tax exceptions and so on.

Proving my point that the rule is that money is taxed when it changes hands and the exceptions are exceptions.

A couple gifting their 18 (or 38) year old kid a car is unlikely to exceed the gift tax exemption.

We should tax money to use it for love. Not love money to not use in anything else than private enjoyment.

The argument is slightly different. It's not economically efficient to allocate wealth to children according to their parents' abilities (as opposed to the children's abilities). Doing the latter (as opposed to the former) will maximize the aggregate wealth of a society.