I don't get all those tears... "wE inVADeRs Are aT a diSadVanTaGE..."... yes and it's intentional. I'm someone who likes to invade, who polices as a Blue, does arena and wears this item so other Blues get their concords.
It's the job of an invader to make it harder for the host, make him use up his estus and to slow him down. Invaders are technically bodyguards of the local boss, just like Blue/Golds/Silvers are bodyguards of the host. Killing the host is just a bonus. Sometimes winning is impossible and sometimes the host died to the pve before I even got close.
Play arena or arrange duels via reddit, from your friendlist or whatever, if you want fair fights.