In one of the many versions of the Ramayana, it is said that once Ram's army had created the bridge to Lanka,
they needed to get Shiva's blessing for which they set up a Yagya.
To give food to the hungry people, to feed dogs etc living creatures and animals etc is not bad,
but it is beneficial only to do charity and Yagya etc through a Complete Saint according to his orders.
The meaning of Adhyay 3 Shlok 17-18 is that one who meditates(dhyaan), he does not even need to perform other Yagyas because(dhyaan)
meditation itself is a Yagya and only that person meditates a lot
who becomes a hermit(one who leaves home and lives in forest) like Shringi rishi.