It's not that wind is not viable, it's just that it's less viable than other sources of energy.
With such a small part of Earth atmosphere pressure, even the high wind speeds it's insufficient.
Energy scales linearly with pressure but with square of wind speed; for wind turbines on Earth the optimal wind speed is 50km/h; 200km/h of Mars would increase the energy by a factor of 16.
Unfortunately, typical Mars pressure of 600Pa is 0.006 of Earth's average 101,300 Pa.
Combining these, it sets wind turbine efficiency on Mars a little short of 10% of corresponding turbine on Earth. Sure with lower gravity and lower expected wind pressure the construction could be significantly lighter, but still one shouldn't expect any very high output, and the construction would need to be BIG to provide any meaningful amount of energy.
OTOH, while Mars, at 1.523679 AU only receives about 0.43 the amount of sunlight reaching Earth, the thin atmosphere blocks and reflects much less of it, meaning solar panels on Mars are about as efficient as on Earth.
So, similarly to employing geothermal energy on the Moon, - yes, it's possible, and no, it's not practical.
If solar panels with tracking systems are roughly the same cost and complexity as wind turbines of the same output on Earth, on Mars you would get about 10% the energy output of solar at roughly the same cost/effort, or the same energy at 10x the cost/effort comparing to solar power. Maybe a little better if the turbines were optimized specifically for Mars conditions - but still far from breaking even.