It's an annoying but very common habit, especially but not exclusively in US English.
You might be more familiar with the habit of referring to "an invite" instead of "an invitation" or "a quote" instead of "a quotation", which fit the same pattern of "compute" instead of "computation". There's even "the big reveal" instead of "the big revelation" - using "revelation" would likely confuse many people, who would assume it was exclusively religious.