Alas, my sympathy! Your experience made me recall the old days when I was hunting job like hell in NYC as a college freshleg while craning my neck for H1-b sponsorship. I cannot say if the compensation itself will turn you away on your H1 application. Rather, to me, your prospective employer is, actually, attempting to sponge-off on you and this salary negotiation alone is heart-wrenching enough. As a CPA in US for many years, I sincerely wish you good luck on your long-awaited green card pursuing and the likes!