The only hard cap on the DHF is that only 1% of the total amount can be spent daily, so a proposal could ask for 77K HBD/day right now. But such a proposal would be functionally different from voting on the comments: a proposal that funds the stabilizer would only increase the DHF funds to the extent that the stabilizer makes a profit (because the base amount from the proposal is just recycled back to the DHF and only the profit gets added). Voting on the comments increases the amount of DHF funds much more directly.
I realized the above might not be clear enough, so I've added some example numbers. Let's assume that the hbdstabilizer is profiting at 0.1% per day right now (this is just a hypothetical number for the sake of an example, profits for hbdstabilizer vary a lot depending on HBD market pricing and I don't know what the current profit percentage is). An extra 10K per day as a proposal would then add 10K HBD * .1% = 10 HBD profit to the DHF. Compare this to 10K HBD added via voting on the hbdstabilizer comments, and you can see it's a dramatic difference (1000x more).
Thanks for the response. I missed all of the posts explaining these things