That will change *ALL* \r in text, not just trailing \r. I do not think that is what dos2ux is supposed to do, though I admit that HP's manual page isn't very clear on that:
dos2ux and ux2dos read each specified file in sequence and write
+ it to
standard output, converting to HP-UX format or to DOS format,
respectively. Each file can be either DOS format or HP-UX forma
A DOS file name is recognized by the presence of an embedded col
delimiter; see dosif(4) for DOS file naming conventions.
If no input file is given or if the argument - is encountered, d
and ux2dos read from standard input. Standard input can be comb
with other files.