Casual is a casualty to all things meaningful.
I disagree. What goes on behind the doors of another man and woman should not in the slightest affect what goes on behind those of others.
While, yes, having a partner who has engaged in casual sex prior to you, may, in an absolute worst-case scenario (and certainly not every time, to every person, by ANY means) subdue some feelings of excitement, experimentation and an overall lessening of the rose-tinted view of sex, it does not mean that their experience is lessened or is less meaningful.
Rather, I feel what is really at stake is pride. Humans, by default, seem to view sex as an embarrassing and awkward practice - which, in realities it can be (is that your foot or mine? etc).
I think any lessening on the other person's part of any "meaningful"-ness could be down to jealousy and insecurity.
Each person is different, ditto the smell of each person's skin and their naughty parts.
Sex is different every single time and is memorable and meaningful every single time.
At least, that's my take on it. And I am, shall we say, a liberal lover.
So, even the most seasoned of sexers can still feel joy, love and the beauty of a moment.
Just like the way that every rainbow, baby's smile or massive bag of doritoes is still amazing, never mind when you last had one.
To clarify, I meant "each person's genitals are different"
Minds out of the gutter, please.