Houston is mediocre and so are those bubble teams, just like Detroit. That's 8 games against mediocre, 4 against bad teams. They easily could have ended up 1-3 versus said bad teams.
I'll give you Houston. But there's something to be said about a team that made the playoffs with a winning record.
I strongly disagree with Washington and Tennessee as mediocre. Indianapolis and Minnesota are debatable. Minnesota was in the playoff race until 2-3 weeks ago. Indianapolis started the year looking good, but Luck getting hurt didn't help much and they had a few bad losses. I will give you those two because they went 8-8 and the definition of mediocre would be 8-8.
For comparison, let's look at NE's schedule:
1. W vs Cardinals (7-8-1, mediocre)
2. W vs Dolphins (10-6, playoff team, or would you define this as mediocre?)
3. W vs Texans (9-7, playoff team but you define them as mediocre)
4. L vs Bills (7-9, mediocre)
5. W vs Browns (1-15, bad)
6. W vs Bengals 6-9-1, bad)
7. W vs Steelers (11-5, playoff, good)
8. W vs Bills (7-9, mediocre)
10. L vs Seahawks (9-7, playoff mediocre)
11. W vs 49ers (2-14, bad)
12. W vs Jets (5-11, bad)
13. W vs Rams (4-12, bad)
14. W vs Ravens (8-8, mediocre)
15. W vs Broncos (9-7 mediocre)
16. W vs Jets (5-11, bad)
17. W vs Dolphins (10-6, mediocre?)
I count 9 mediocre teams, 6 bad teams, and 1 good team... Not saying Detroit is New England but if we are going to criticize a team based on their strength of schedule, let's look no further than NE. I think if Detroit had NE's schedule they would have over 10 wins easily.