Honestly, attachment to sex rather than gender as a social construction won't create a utopia without the subjugation of one's presentation, background, or experience from existing. Recognizing that sex and gender are both socially constructed and while they sometimes inform one another, they won't always, and that trans people absolutely can attest to this and are integral to making change for a better world are insurmountably important. If your desire for a "better world" coincidentally doesn't include us, what you desire isn't a better world where people are free - it is subjugation by a different name.