I don't think that's right, it should be able to do 60Hz. It seems HDMI 1.4 can do 30Hz for a 4K resolution, and 4K has over twice the pixels than what 1440p has. This should then mean that 1440p at 60Hz will fit fine into the bandwidth that HDMI 1.4 has.
Here's what I mean about the amount of pixels:
3840 * 2160 = 8,294,400 <-- 4K resolution
2560 * 1440 = 3,686,400 <-- 1440p resolution