The Get Rule is a PlainWords* rule. The principle is to use the verb to get wherever possible. The purpose is to minimise the amount of vocabulary that the reader needs, and the only criterion is that the context is sufficient that the meaning conveyed by 'get' is sufficient to cover the meaning conveyed by the (possibly more precise) word that get is replacing.
is better than
since retriving is an obscure latinism, and has no more meaning than 'finding and bringing back' or 'fetching' both of which are in the (rather special) meaning-space** of get. In this specific example, loading data might be better than either, because it is domain-specific***.
Get is a very special animal indeed; it is a metasyntactic variable verb - essentially a placeholder sound whose meaning is conveyed by the surrounding context. What makes it special is that its possible meaning is restricted to notions of transfer. It is the direct equivalent of the latin verb ferre (fero ferre tuli latum) from which we get both transfer and translate.
* "The Complete Plain Words", by Sir Ernest Gowers, is one of my main inspirations
** the linguistic equivalent of phase-space, meaning-space is described as the set of all possible meanings of a given word, excluding identically spelt homonyms
*** referring to the domain of a technical term.