It's just luck, there are no 'conspiracies' to get red packs.
Stands to reason that out of the million or so players then a small percentage will get no injuries whilst at the other end of the scale an equally small percentage will have their whole squad killed in a bus crash on the way to the game (exaggeration) whilst the majority have a few a week.
Point being is that when you do get a spate of injuries then you notice them because of the negative impact, therefore you feel like the game is picking on you.
A long run of no injuries doesn't have quite the same impact and you feel less likely to start a thread about how well the game is treating you.
Just out of balance, we are 24 days into the season and I've had 4 injuries so far.