No, they aren't. DLC is an expansion upon the content. The best case scenario for mtx that do not affect gameplay are cosmetic only.

If a game in any way has anything else than cosmetic mtx, the game is worse.

"But you don't have to buy it!" Is how I often see them defended, the subtext being that, if I don't buy them it doesn't affect my experience.

Here is the secret, games with mtx are designed to have problems and they sell you the solution. They are designed WORSE intentionally, so you will spend money to bypass the inconveniences. Often your time.

A perfect example is something like long standing games selling boosts to max level. They're aware the old content is dead, and they're aware the only people playing it are the people who don't want to spend money. Why don't they fix that?

The answer is they did, they decided that inconvenience was acceptable in their game in order to convince the player to spend money.

MTX is not content, often it's used to bypass content or save time. DLC is content. DLC often expands upon the experience of the game. MTX worsens the experience of the game just buy existing. Dlc doesn't change your experience if you don't purchase or use it. MTX changes the game at a base level no matter if you spend money or not.

I'm sorry that you just take what Papa Activison says you have to take. Poor guy.