The main criticisms of the OKR (Objectives and Key Results) system as reported in the case of ByteDance and other major tech companies are as follows:

1. Lack of Flexibility: OKRs are often set at the beginning of a quarter and are not easily adjustable, making it difficult for teams to adapt to changing circumstances or new opportunities that may arise.

2. Focus on Short-Term Goals: OKRs often emphasize short-term objectives, which can lead to neglecting long-term strategy and innovation.

3. Over-emphasis on Quantitative Results: OKRs primarily focus on quantitative results, which can lead to neglecting qualitative aspects of work and may not reflect the full value of an individual's or team's contributions.

4. Increased Bureaucracy: The process of setting, tracking, and reviewing OKRs can be time-consuming and bureaucratic, leading to a decrease in productivity and efficiency.

5. Lack of Alignment: OKRs may not always align with the company's overall strategy, leading to siloed efforts and misalignment between teams.

6. Demotivating: When OKRs are used as a tool for performance evaluation, they can become demotivating for employees, especially when targets are set too high or are not achievable.

7. Difficulty in Measurement: Some objectives or key results may be difficult to measure accurately, leading to ambiguity and confusion.

8. Stifling Innovation: The focus on achieving specific goals can stifle innovation and experimentation, as employees may feel pressured to meet targets rather than explore new ideas.

These criticisms highlight the challenges associated with implementing and maintaining an effective OKR system in large tech companies like ByteDance. It's important for organizations to carefully consider these potential drawbacks when deciding whether to adopt an OKR approach.