Yeah I though about it in the past when people kept saying that it doesn't really straighten highly textured curly hair.
From what I've experienced you dont want to texturize with a relaxer first hand if you want to only loosen your curls. I know for my hair it went wavy straight instead of looser curls. If you have dyed ends or highlights it may still not give you the best outcome. Any hair that has been chemically altered will be looser and silkier than the virgin hair. I would suggest getting the texturized effect on virgin hair. And just do it as many times as needed until you get the looseness you desire. After that you would probably want to wait every 3 months or so before doing it again. Or wait until you see signs that your hair is starting to revert back to normal. This way you dont straighten out your hair too much. This is the only way I can imagine it working out nicely.