Not actually correct.
With sand filters, the dirt tends to become part of the filter media. As a result, the filter removes finer and finer particles, as the cycle continues. This is particularly important during algae cleanup.
On the other hand, sand in filters that are rarely or never cleaned can become 'goo-ey'.
A better solution, rather than excessive backwashing, is adding your chlorine via the skimmer. This will break down the oils and goo, that may otherwise accumulate. Just be SURE that there is no MIXING of chemicals going on -- do NOT pour bleach into a skimmer that has a chlorine tab in it.
And particularly, do not dump cal hypo granules in, if you have added stabilizer to the skimmer in the last 3 - 4 days.