It's not just the special effects that I don't like in a lot of older movies, it's also things like the pacing which, as a modern audience, I am used to being much faster and considered. Also, there's the issue of the time period's culture, which as a modern audience I may find repulsive. Just think of all the old movies featuring blackface or rapey romance scenes.

I'm not saying that I don't like old movies at all. I do, however, think that the differences between the eras in terms of technology, culture, performances and the development of the process of movie making significantly impacts the enjoyment that I personally get out of a lot of these movies. Not all of them, but a lot.