Why does current associated with a rectifier said to have both ac and dc components?
AC is actually a term that has quite a vague meaning in EE.

See this answer.

Rectified AC is really a modulated voltage with a single polarity. As such it is actually an AC signal with a DC bias that keeps it always in one polarity.

So this...



Is also this...



BTW: Actually if you want to be pedantic, a rectifier delivers Alternating  and Direct VOLTAGE components. The current could be anything depending on the load. The C in AC and DC is actually a generalization misnomer.