The flamer is a weapon best paired with something that disrupts chem cycles. As Sammy and Patched point out, it is a weapon that starts out seeming unbalanced because without chemspray applied to vital components before the engagement starts you are in deep crap. With it a flame thrower alone is basically useless. Pair it with something that disrupts chem cycles (carronade or gatling say) and it is a effective, reasonably well balanced weapon that tips longer engagements in your favour.
I'm sorry you were paired against very experienced crews. This is likely a result of MM determining from the novice games that you played in that you are pretty good, giving you a high win rate. There aren't many experienced players in the MM queue at any given time, so they are often just paired off against whatever the matchmaker thinks are the next best players available. On the plus side you can be proud that is you, on the down side 1000+ matches experience is hard to overcome even with great twitch reflexes and a sharp mind.
Once out of novice games all players have access to all the same ships and tools. This is not a level thing, there is just a tactic (flame spam) which enemies are exploiting to beat you. Once you know how to counter it (chem cycles), it will be less of a problem. Of course then you will find new tactics you will have to counter (snipe heavy builds, meta builds, blending, and on and on), this game is absurdly deep. If you want someone to go over the basics of chem cycles with you and your crew feel at liberty to contact me in game. The basics are pretty simple. A word of advice though, always, always, always make sure you have at least one engineer with chemspray unless there is a reason you wont need it (instagib mobulas or spires frequently run chem spray free). Experienced pilots check the enemy load-outs and if you do not have any chemspray they are going to include something with fire damage, likely a flame thrower, possible more than one. Simply having your engineers bring chemspray will reduce the amount of fire spam you encounter, even if you are using it sub-optimally.