Some do, some don't... it's kinda hard to judge since Eirs are probably the least commonly seen class if you look at the people generally considered to be good at PvP, but most of the good PvPers won't cry about a heal being used, I think.
Of course, most people will still get annoyed if your strategy revolves around running in circles around a wall/pillar in the castle or temple maps while spamming heals and ranged attacks, but that's why people like to play forest/city/team tournament.
"It is not a disgrace to fail. Failing is one of the greatest arts in the world," however --
"Believe and act as if it is impossible to fail." ~ Charles Kettering