You are spot on about the market risk factor.
If we keep that aside for a moment, and if someone has the option of locking money for 5 years or more, then ULIP and FD gives about the same returns pre tax.
With the added advantage the you get to add money in ULIP over a period of time instead putting all the money in one shot in FD on day zero. Additionally, on maturity FD is taxable as per your slab but ULIP is not (if eligible for 10 (10D)). Plus ULIP gives you some life cover which FD doesn't.
This is purely a comparison of FD vs ULIP and as an investment tool.
BTW, this is not an argument, but just a discussion.
Of course there are better investment tools and in absolute sense ULIP should never be taken as an investment tool.