It’s tough to extrapolate a general rule from a specific incident especially when a lot of the background is unknown. Having said that, I think the guiding principal behind the advice given in that shiur is to protect oneself from experiences that can dissuade one from performing such mitzvot down the road, r”l. But, it doesn’t necessarily mean that not receiving emotional reward for one’s efforts diminishes the mitzvah itself in any way. The ultimate reward for performing mitzvot isn’t necessarily doled out in this world.
Also, consider that sometimes the situation isn’t so cut and dry. Perhaps the unappreciative recipient of your kindness didn’t perceive the benefit of your actions.
I remember a comedy skit by Abbott & Costello in which Costello sees a Boy Scout help an elderly woman cross the street and in appreciation the woman gives the young man a coin (big money in those days). Figuring he’d found a way to earn some sorely needed income, he proceeds to drag an elderly woman across the street only to be rewarded with a clop on the head with an umbrella.