DND_Reborn
The High Aldwin
PHB p147:-
"In many cases, an improvised weapon is similar to an actual weapon."
Meaning, first, it is not an actual weapon, and second, in many cases an improvised weapon is not similar to an actual weapon.
Weapon = weapon.
Improvised weapon = not weapon, used as if it were a weapon.
'Weapon' is an object designed to be a weapon. The improvised weapon rules provide a way to use objects in combat that are not weapons, and ways to use things that are weapons in a way they were not designed, like hitting someone upside the head with a crossbow.
Things are what they are, even if you use them in inappropriate ways. You can get a piggy-back from a friend, but that doesn't allow him to benefit from the rules for mounts.
The spell magic weapon says, "You touch a nonmagical weapon." Can I cast it on a magical weapon? After all, I could use a magical weapon as if it were not magical? No, no more than you can cast the spell on a painting or a viking longship. The fact that the rules provide a way to adjudicate a PC hitting someone over the head with a painting (or a longship) does not make either a valid target for the spell.
Hold person says, "Choose a humanoid you can see..." Can you cast it on a vampire? After all, they conform to the natural language meaning of 'humanoid': two arms, two legs, one head, one body? No, because the term 'humanoid' is a game term with a specific meaning, and that meaning excludes creatures that are not (game term) humanoids, like undead.
And 'weapon' is also a game term, meaning 'an object designed to be a weapon'. Weapons are simple or martial, melee or ranged. The term does not mean, "anything you pick up and hit people with". If it did, there would be no section on 'improvised weapons', it would just be 'weapons' and include objects like paintings and toasters and....every object in the world!
Bolding points doesn't make them more meaningful, it only seems like you're arguing now.
And as I said before:
Either way, since it is a matter of interpretation, there is no use debating it since we are both, in fact, correct in our own way.
This will never be a "I'm right, you're wrong" argument, but please, continue if you must...