This is true that the tax office considers relocation expenses as living costs. The living costs are generally not tax-deductible.
However, in the canton of Zurich there is a rule which allows to deduct relocation costs in some cases.
If an individual is forced to move because of the reasons associated with this current employer/company, he or she is permitted to deduct the relocation costs. That means, if you moved to Zurich because your company moved here and if you had not moved, you would have lost your job, then you can claim the appropriate deduction.
If you had simply found a new job in Zurich and had moved here voluntary (it is your decision, not a plight), then no deduction is possible.
This is why in this particular case you can deduct your relocation costs.