A bit more elaborated answer gathered from my comments above:
First of all- what do you mean by aggressive- Shaky? fast? high pitched?
If the headwind is stable- it changes the Ground speed at which the plane rotates, making it lower. After that, the aircraft climbs at the same pitch angle as always, once it transitioned to the stage of acceleration from V2. What does change a lot is the rate of climb per distance, nor per time. The situation is different if it is gusty- then the scenario is that it's all very bumpy, and planes do trade a bit of speed for pitch due to the logic of the aircraft flight algorithm- constant thrust, changing pitch. It will be elaborated further down the answer.
If it's unstable at low alt, maybe they maintained a high pitch, low speed, flaps down climb to clear the turbulent air (they just maintained a lower speed all the way out of the boundary layer). Finally, maybe they performed a full thrust take off- which is sometimes performed when wind shear is predicted, resulting in a very steep pitch after take off for such a light plane (1-hour flight).
If the wind changes and adds additional 30 knots of headwind in an instance- and stays there- meaning another stable mass of air- the pitch will become higher but only until the aircraft loses the energy it gained from the pitch up- after which it will retain it's original attitude and continue climbing with the same rate of climb- because after some time the pitch angle wouldn't hold the speed as the aircraft transitions to flying in the new "air mass".
Elaborating on the concept of fixed thrust: These aircraft are built in a way that they maintain a uniform setting of thrust throughout the whole duration of the climb, decided after their performance calculations. Meaning- if there is a change in a headwind- they will pitch a little bit higher. This is possible due to the logic of the machine that rotates and keeps a velocity higher than V2, which is the safe airborn speed- meaning there is a margin.
Next: as for sudden decreasing headwinds- the aircraft always corrects it's pitch accordingly, and they are not as edgy as little light planes. Finally- the pilots can always lower the nose or apply more thrust or both. In addition- when conditions prevail that dictate the usage of wind shear conditions in the calculations- the aircraft is rotated at a higher velocity than the normal V2, giving it further margin, and they usually use flaps 20 (or the equivalent in an airbus which I am not familiar with) in order to support further fluctuations in wind speed. All in all- the aircraft has margins.
As for the actual technique the plane maintains pitch- I would assume that it has its barriers and the fluctuations in attitude are gentle enough in order not to get to high or low exactly for the reason you mentioned above. If you maintain a constant pitch attitude- you can also exceed the flaps speed. Final note- when encountering a real wind shear- 15 knots deviation, 5 degrees of pitch fluctuation, 1 dot of GS deviation, 500 FPM vertical speed deviation, the pilots would engage the wind shear maneuver- meaning TOGA (initiating a sequence of actions that are built to sustain a wind shear situation), full thrust to maintain possitive vertical speed until clear.
I hope this is not too technical, will be happy to explain everything.
I you understand the reason the aircraft acted the way it acted- maybe you will be able to point out exactly how it felt.