Ok wait, wait, wait...
Maybe it's just me, but I didn't take this thread at all the way others did, and probably because I see MuseofTroy's avatar shows that she has straightened hair.
Of course we need to ask her, but maybe she meant that using a perm for straightening was worse than the old-school style of pressing... again, since the OP does have straight hair, I don't think she was saying that "straightening" was evil, but that she was taught that perms/relaxers were evil because they damaged the hair.
Back when relaxers first came out, they were a lot more damaging than they are today and I have heard plenty of stories from women who got relaxers in the 60s and 70s who say that they took ALL of their hair out... so Muse's aunt might be working from that experience.
In my family for example, no one relaxes, but they all have straight hair. They just use pressing combs and flat irons. Now we've all had relaxers at some point in our lives, but we've discovered that our hair collectively doesn't do well with even the mildest relaxers and the best conditioners to protect against damage. So my cousins went back to pressing and so did my mom. My aunt and grandma never relaxed, they just pressed or got roller sets. I was the rebel and went natural.
To this day, the women in my family will speak badly about perms, but they still straighten. They're not speaking about the practice of straightening, but the actual perm/relaxer itself. People will even say that they have "nice hair" because they don't perm it, but press it instead, which supposedly damages the hair less and keeps the thickness and volume (that's the perception anyway... it's true for my family, at least)
When I read Muse's post and saw that her aunt was making the comment, I figured that's what she meant since a lot of older people don't like relaxers based on their experiences.
I honestly don't think that she was trying to do a relaxed vs. natural thing... again, she has straightened hair!
Just my 2 cents!