If Adi Shankara was trying to avoid the Chandala then he was simply following the injunctions of Scriptures. So, if you want to blame someone (or something) here, then blame the Scriptures. Because Adi Shankara was simply adhering to them.
See the following verses from Manu Smriti:
3.239. A Chandala, a village pig, a cock, a dog, a menstruating woman, and a eunuch must not look at the Brahmanas while they eat.
5.85. When he[a brahmin] has touched a Chandala, a menstruating woman, an outcast, a woman in child bed, a corpse, or one who has touched a (corpse), he
becomes pure by bathing.
10.51. But the dwellings of Chandalas and Svapakas shall be outside the village, they must be made Apapatras, and their wealth (shall be) dogs
10.53. A man who fulfils a religious duty, shall not seek intercourse with them; their transactions (shall be) among themselves, and their
marriages with their equals.
11.175. A Brahmana who unintentionally approaches a woman of the Chandala or of (any other) very low caste, who eats (the food of such
persons) and accepts (presents from them) becomes an outcast;
And from Parashara Smriti:
- For sleeping together with many of the Chandala caste, let a Brahman fast for full three nights. If he treads a path that a
Chandala has trodden, his sin is removed by a remembrance of the
- On seeing a Chandala, let him look at the sun without a moment's delay. For touching a Chandala, let him bathe with his clothing on.
So, Adi Shankara was simply following these instructions.
In any case, these verses should not taken as applicable only to a particular caste of people that is solely determined by birth. A Chandala is also the one who may not be that by birth but who is acting like one.
He who sets his face against righteousness, is but a Chandala by his
acts. He gains nothing by being a mendicant, or by worshiping the
Also, what Lord Shiva said simply means "What is the difference between a Chandala and a Brahmin when Atma-Gyana (Brahma Gyana, Knowledge of the Self) is obtained?
When Atma Gayna is obtained then one is free from all vedhas( dualities, differences) but till that (state of avedha) is achieved the vedhas are very much there.
When one achieves Atma Gyana there is no karma for him (good or bad) and there are no rules for him. There is no need for him then to follow the Scriptural injunctions either.
But for all other persons those rules laid down in Shastras should always be followed.