The Rikers as I recall were antagonistic right off the bat. I would imagine having yourself blended with someone else might be even worse.
In Riker's defense, he saved his duplicate from death. I thought it was interesting how TNG handled the transporter duplicate storyline, with both being clones of the original.
I hated how DS9 made Thomas Riker the bad guy and concluded his storyline. I like to pretend his story actually ended in TNG, and that Thomas is still out there in Starfleet.