Absolutely. I am 100% in favor of a Sci-Fi Channel boycott. I'm not saying it will do any good at this late date, but if you want to boycott, in the immortal words of The Executive, "nobody's stopping you!"
I have personally stopped boycotting Sci-Fi, not because I feel they'll never finish off Sliders, but because quite frankly I can't stand any of their shows -- therefore I feel a boycott to be unnecessary.