That doesn't undermine their statement at all. They wrote hundreds or thousands, perhaps you misread it as hundreds of thousands? 67,000 killed per your link, assuming only 1% were LGBTQ, means around 670 LGBTQ people killed, which falls well within the standard definition of "hundreds". Even if they only make up 0.5% of the population, it's still hundreds. And to hit "tens" they only need to be about 0.1% of the Gazan population.