Those are not flashpoints they're heroic quests...
Have you looked to your servers population before coming crying to the forums? Is the ratio between factions balanced or all over the place? Are you on one of the older servers where the people flying through the quests are probably capped, or a newer one where people may still be arsing around at level 20~ on their alts?
vvvvvvTHIS IS MASSIVELY RELEVANTvvvvvvPeople have this weird shyness thing in regards to forming a group. You will be honestly surprised how many people will respond to 'LFM x heroic quests!' over someone mindlessly spamming 'LFG x' 'LFG x' 'LFG x' every 5 seconds.