If you are an 18+ adult and need 'trigger warnings' by others to get through life, then perhaps you should get off the internet :P
It is not the responsibility of ANYONE else to account for infantilized inadequate pseudo-children masquerading as adults and demanding that others cater to them. That's how CHILDREN make demands. They are not adults and not suitable to be treated as adults so therefore they should be denied access to adult content without further question or consideration. Take your trigger warnings and bugger the hell off the net already.
Literally the only people that I believe could possibly have a strong case for desiring 'trigger' warnings would be military veterans with PTSD. That's about the only type of group I could sympathize with to some extent but I still wouldn't feel 'trigger' warnings are a good idea. The individual needs treatment and society should not be required to bend over backwards for their individual situation.