The band later posted a statement to Facebook, which you can read below.
"Security guards are 99.9% helpful but it disgusted us to witness the 0.1% at Warped Tour in Dallas, (a local security guard not an official Warped security) who was built like 'Duke Nukem' restrain and choke a fan in the crowd for 'moving towards the barrier'. His head was literally turning blue and all we could read on his lips were 'I can't breathe'. It was completely unnecessary, we did our best to intervene, pulling on his arm to try allow air in whilst every other guard just stood back. If you're a security guard reading this you need to understand that this is a metal show, not a UFC death match. And if you're in the mosh enjoy yourself and be respectful but you also need to be aware of the consequences - which shouldn't be the possibility of being put into submission to the point of unconsciousness. Please take care and look out for one another. If anyone else has any videos or photos please let us know so we can help find justice - IHW / Jake"