Here's why:
* Gearfried's effect states: "When this card declares an attack, you can discard 1 card; negate the effect of 1 face-up card your opponent controls, and destroy it."
* The limitation of the effect is that you can negate the effect of *a face-up card your opponent controls*.
* The problem is that the spell or trap that prevents you from activating spells or traps is preventing its own activation. In other words, it is controlling its own effect.
Therefore, Gearfried's effect cannot target a card that is preventing its own activation, as it is not under the control of your opponent.
Example:
Imagine your opponent activates "Solemn Warning" to negate the activation of your spell or trap. You cannot use Gearfried's effect to negate "Solemn Warning" because "Solemn Warning" is not under your opponent's control; it is under the control of its own effect.
Instead:
You would need to find a way to bypass the effect of the spell or trap that is preventing you from activating spells or traps. This could involve:
* Using a card that specifically negates the effects of spells or traps, such as "Solemn Judgment".
* Using a card that allows you to activate spells or traps without their activation being negated, such as "Forbidden Lance".
* Using a card that removes the spell or trap from the field, such as "Torrential Tribute".
Remember, carefully read the text of cards and their effects to understand how they interact with each other.