The gif is fine, but when it gets enlarged by a browser, it'll get blurred. This doesn't happen on Pixelation because Pixelation has special CSS in place that tells the browser to use Nearest Neighbour (non-blurry) resampling. Most websites do not have such CSS because the "blurry" upscaling works well for non-pixel art images such as photos and paintings.
If you're using a high-DPI display such as some phones and tablets, then all images are scaled by default, hence the image appearing blurry without any "obvious" zooming.